Add missing ax_prepend_flag.m4 macro
diff --git a/Makefile.in b/Makefile.in
index d665609..14d1e3a 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -261,7 +261,6 @@
subdir = .
ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
am__aclocal_m4_deps = $(top_srcdir)/m4/ac_func_fseeko.m4 \
- $(top_srcdir)/m4/ax_append_flag.m4 \
$(top_srcdir)/m4/ax_c___attribute__.m4 \
$(top_srcdir)/m4/ax_cflags_warn_all.m4 \
$(top_srcdir)/m4/ax_check_compile_flag.m4 \
@@ -275,6 +274,7 @@
$(top_srcdir)/m4/ax_lang_compiler_ms.m4 \
$(top_srcdir)/m4/ax_opencl.m4 \
$(top_srcdir)/m4/ax_prefix_config_h.m4 \
+ $(top_srcdir)/m4/ax_prepend_flag.m4 \
$(top_srcdir)/m4/ax_prog_perl_version.m4 \
$(top_srcdir)/m4/ax_pthread.m4 \
$(top_srcdir)/m4/ax_require_defined.m4 \
diff --git a/aclocal.m4 b/aclocal.m4
index 07f4071..dd4347f 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1253,7 +1253,6 @@
]) # _AM_PROG_TAR
m4_include([m4/ac_func_fseeko.m4])
-m4_include([m4/ax_append_flag.m4])
m4_include([m4/ax_c___attribute__.m4])
m4_include([m4/ax_cflags_warn_all.m4])
m4_include([m4/ax_check_compile_flag.m4])
@@ -1267,6 +1266,7 @@
m4_include([m4/ax_lang_compiler_ms.m4])
m4_include([m4/ax_opencl.m4])
m4_include([m4/ax_prefix_config_h.m4])
+m4_include([m4/ax_prepend_flag.m4])
m4_include([m4/ax_prog_perl_version.m4])
m4_include([m4/ax_pthread.m4])
m4_include([m4/ax_require_defined.m4])
diff --git a/configure b/configure
index ce4b1e9..f10e1c8 100755
--- a/configure
+++ b/configure
@@ -4566,7 +4566,7 @@
MAGICK_VERSION=7.0.10-11
-MAGICK_GIT_REVISION=17210:e42a1c49b:20200428
+MAGICK_GIT_REVISION=17221:d5e837e7f:20200503
# Substitute library versioning
@@ -8521,48 +8521,156 @@
-ac_ext=c
-ac_cpp='$CPP $CPPFLAGS'
-ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
-ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
-ac_compiler_gnu=$ac_cv_c_compiler_gnu
-
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking CFLAGS for maximum warnings" >&5
-$as_echo_n "checking CFLAGS for maximum warnings... " >&6; }
-if ${ac_cv_cflags_warn_all+:} false; then :
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for C compiler vendor" >&5
+$as_echo_n "checking for C compiler vendor... " >&6; }
+if ${ax_cv_c_compiler_vendor+:} false; then :
$as_echo_n "(cached) " >&6
else
- ac_cv_cflags_warn_all="no, unknown"
-ac_save_CFLAGS="$CFLAGS"
-for ac_arg in "-warn all % -warn all" "-pedantic % -Wall" "-xstrconst % -v" "-std1 % -verbose -w0 -warnprotos" "-qlanglvl=ansi % -qsrcmsg -qinfo=all:noppt:noppc:noobs:nocnd" "-ansi -ansiE % -fullwarn" "+ESlit % +w1" "-Xc % -pvctl,fullmsg" "-h conform % -h msglevel 2" #
-do CFLAGS="$ac_save_CFLAGS "`echo $ac_arg | sed -e 's,%%.*,,' -e 's,%,,'`
- cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+
+ vendors="
+ intel: __ICC,__ECC,__INTEL_COMPILER
+ ibm: __xlc__,__xlC__,__IBMC__,__IBMCPP__,__ibmxl__
+ pathscale: __PATHCC__,__PATHSCALE__
+ clang: __clang__
+ cray: _CRAYC
+ fujitsu: __FUJITSU
+ sdcc: SDCC,__SDCC
+ sx: _SX
+ portland: __PGI
+ gnu: __GNUC__
+ sun: __SUNPRO_C,__SUNPRO_CC,__SUNPRO_F90,__SUNPRO_F95
+ hp: __HP_cc,__HP_aCC
+ dec: __DECC,__DECCXX,__DECC_VER,__DECCXX_VER
+ borland: __BORLANDC__,__CODEGEARC__,__TURBOC__
+ comeau: __COMO__
+ kai: __KCC
+ lcc: __LCC__
+ sgi: __sgi,sgi
+ microsoft: _MSC_VER
+ metrowerks: __MWERKS__
+ watcom: __WATCOMC__
+ tcc: __TINYC__
+ unknown: UNKNOWN
+ "
+ for ventest in $vendors; do
+ case $ventest in
+ *:)
+ vendor=$ventest
+ continue
+ ;;
+ *)
+ vencpp="defined("`echo $ventest | sed 's/,/) || defined(/g'`")"
+ ;;
+ esac
+
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int
main ()
{
+#if !($vencpp)
+ thisisanerror;
+#endif
+
;
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
- ac_cv_cflags_warn_all=`echo $ac_arg | sed -e 's,.*% *,,'` ; break
+ break
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-done
-CFLAGS="$ac_save_CFLAGS"
+ done
+
+ ax_cv_c_compiler_vendor=`echo $vendor | cut -d: -f1`
fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_cflags_warn_all" >&5
-$as_echo "$ac_cv_cflags_warn_all" >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_c_compiler_vendor" >&5
+$as_echo "$ax_cv_c_compiler_vendor" >&6; }
+
+ ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
-case ".$ac_cv_cflags_warn_all" in
- .ok|.ok,*) ;;
- .|.no|.no,*) ;;
- *)
+
+
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking CFLAGS for most reasonable warnings" >&5
+$as_echo_n "checking CFLAGS for most reasonable warnings... " >&6; }
+if ${ac_cv_cflags_warn_all+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+
+ ac_cv_cflags_warn_all=""
+ ac_save_cflags_warn_all_found="yes"
+ case "$ax_cv_c_compiler_vendor" in #(
+ intel) :
+ ac_cv_cflags_warn_all="-w2" ;; #(
+ ibm) :
+ ac_cv_cflags_warn_all="-qsrcmsg -qinfo=all:noppt:noppc:noobs:nocnd" ;; #(
+ pathscale) :
+ ;; #(
+ clang) :
+ ac_cv_cflags_warn_all="-Wall" ;; #(
+ cray) :
+ ac_cv_cflags_warn_all="-h msglevel 2" ;; #(
+ fujitsu) :
+ ;; #(
+ sdcc) :
+ ;; #(
+ sx) :
+ ac_cv_cflags_warn_all="-pvctl,fullmsg" ;; #(
+ portland) :
+ ;; #(
+ gnu) :
+ ac_cv_cflags_warn_all="-Wall" ;; #(
+ sun) :
+ ac_cv_cflags_warn_all="-v" ;; #(
+ hp) :
+ ac_cv_cflags_warn_all="+w1" ;; #(
+ dec) :
+ ac_cv_cflags_warn_all="-verbose -w0 -warnprotos" ;; #(
+ borland) :
+ ;; #(
+ comeau) :
+ ;; #(
+ kai) :
+ ;; #(
+ lcc) :
+ ;; #(
+ sgi) :
+ ac_cv_cflags_warn_all="-fullwarn" ;; #(
+ microsoft) :
+ ;; #(
+ metrowerks) :
+ ;; #(
+ watcom) :
+ ;; #(
+ tcc) :
+ ;; #(
+ unknown) :
+
+ ac_cv_cflags_warn_all=""
+ ac_save_cflags_warn_all_found="no"
+ ;; #(
+ *) :
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Unknown compiler vendor returned by AX_COMPILER_VENDOR" >&5
+$as_echo "$as_me: WARNING: Unknown compiler vendor returned by AX_COMPILER_VENDOR" >&2;}
+ ac_cv_cflags_warn_all=""
+ ac_save_cflags_warn_all_found="no"
+
+ ;;
+esac
+
+ if test "x$ac_save_cflags_warn_all_found" = "xyes"; then :
+ if test "x$ac_cv_cflags_warn_all" != "x"; then :
+
if ${CFLAGS+:} false; then :
case " $CFLAGS " in #(
@@ -8574,7 +8682,7 @@
test $ac_status = 0; } ;; #(
*) :
- as_fn_append CFLAGS " $ac_cv_cflags_warn_all"
+ CFLAGS="$ac_cv_cflags_warn_all $CFLAGS"
{ { $as_echo "$as_me:${as_lineno-$LINENO}: : CFLAGS=\"\$CFLAGS\""; } >&5
(: CFLAGS="$CFLAGS") 2>&5
ac_status=$?
@@ -8593,10 +8701,18 @@
test $ac_status = 0; }
fi
- ;;
-esac
-ac_ext=c
+fi
+
+else
+ true
+
+fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_cflags_warn_all" >&5
+$as_echo "$ac_cv_cflags_warn_all" >&6; }
+
+ ac_ext=c
ac_cpp='$CPP $CPPFLAGS'
ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
@@ -8821,65 +8937,6 @@
fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for C compiler vendor" >&5
-$as_echo_n "checking for C compiler vendor... " >&6; }
-if ${ax_cv_c_compiler_vendor+:} false; then :
- $as_echo_n "(cached) " >&6
-else
- # note: don't check for gcc first since some other compilers define __GNUC__
- vendors="intel: __ICC,__ECC,__INTEL_COMPILER
- ibm: __xlc__,__xlC__,__IBMC__,__IBMCPP__
- pathscale: __PATHCC__,__PATHSCALE__
- clang: __clang__
- cray: _CRAYC
- fujitsu: __FUJITSU
- sdcc: SDCC, __SDCC
- gnu: __GNUC__
- sun: __SUNPRO_C,__SUNPRO_CC
- hp: __HP_cc,__HP_aCC
- dec: __DECC,__DECCXX,__DECC_VER,__DECCXX_VER
- borland: __BORLANDC__,__CODEGEARC__,__TURBOC__
- comeau: __COMO__
- kai: __KCC
- lcc: __LCC__
- sgi: __sgi,sgi
- microsoft: _MSC_VER
- metrowerks: __MWERKS__
- watcom: __WATCOMC__
- portland: __PGI
- tcc: __TINYC__
- unknown: UNKNOWN"
- for ventest in $vendors; do
- case $ventest in
- *:) vendor=$ventest; continue ;;
- *) vencpp="defined("`echo $ventest | sed 's/,/) || defined(/g'`")" ;;
- esac
- cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h. */
-
-int
-main ()
-{
-
- #if !($vencpp)
- thisisanerror;
- #endif
-
- ;
- return 0;
-}
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
- break
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
- done
- ax_cv_c_compiler_vendor=`echo $vendor | cut -d: -f1`
-
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_c_compiler_vendor" >&5
-$as_echo "$ax_cv_c_compiler_vendor" >&6; }
-
@@ -9407,49 +9464,58 @@
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for C compiler vendor" >&5
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for C compiler vendor" >&5
$as_echo_n "checking for C compiler vendor... " >&6; }
if ${ax_cv_c_compiler_vendor+:} false; then :
$as_echo_n "(cached) " >&6
else
- # note: don't check for gcc first since some other compilers define __GNUC__
- vendors="intel: __ICC,__ECC,__INTEL_COMPILER
- ibm: __xlc__,__xlC__,__IBMC__,__IBMCPP__
- pathscale: __PATHCC__,__PATHSCALE__
- clang: __clang__
- cray: _CRAYC
- fujitsu: __FUJITSU
- sdcc: SDCC, __SDCC
- gnu: __GNUC__
- sun: __SUNPRO_C,__SUNPRO_CC
- hp: __HP_cc,__HP_aCC
- dec: __DECC,__DECCXX,__DECC_VER,__DECCXX_VER
- borland: __BORLANDC__,__CODEGEARC__,__TURBOC__
- comeau: __COMO__
- kai: __KCC
- lcc: __LCC__
- sgi: __sgi,sgi
- microsoft: _MSC_VER
- metrowerks: __MWERKS__
- watcom: __WATCOMC__
- portland: __PGI
- tcc: __TINYC__
- unknown: UNKNOWN"
- for ventest in $vendors; do
- case $ventest in
- *:) vendor=$ventest; continue ;;
- *) vencpp="defined("`echo $ventest | sed 's/,/) || defined(/g'`")" ;;
- esac
- cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+
+ vendors="
+ intel: __ICC,__ECC,__INTEL_COMPILER
+ ibm: __xlc__,__xlC__,__IBMC__,__IBMCPP__,__ibmxl__
+ pathscale: __PATHCC__,__PATHSCALE__
+ clang: __clang__
+ cray: _CRAYC
+ fujitsu: __FUJITSU
+ sdcc: SDCC,__SDCC
+ sx: _SX
+ portland: __PGI
+ gnu: __GNUC__
+ sun: __SUNPRO_C,__SUNPRO_CC,__SUNPRO_F90,__SUNPRO_F95
+ hp: __HP_cc,__HP_aCC
+ dec: __DECC,__DECCXX,__DECC_VER,__DECCXX_VER
+ borland: __BORLANDC__,__CODEGEARC__,__TURBOC__
+ comeau: __COMO__
+ kai: __KCC
+ lcc: __LCC__
+ sgi: __sgi,sgi
+ microsoft: _MSC_VER
+ metrowerks: __MWERKS__
+ watcom: __WATCOMC__
+ tcc: __TINYC__
+ unknown: UNKNOWN
+ "
+ for ventest in $vendors; do
+ case $ventest in
+ *:)
+ vendor=$ventest
+ continue
+ ;;
+ *)
+ vencpp="defined("`echo $ventest | sed 's/,/) || defined(/g'`")"
+ ;;
+ esac
+
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int
main ()
{
- #if !($vencpp)
- thisisanerror;
- #endif
+#if !($vencpp)
+ thisisanerror;
+#endif
;
return 0;
@@ -9459,8 +9525,9 @@
break
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
- done
- ax_cv_c_compiler_vendor=`echo $vendor | cut -d: -f1`
+ done
+
+ ax_cv_c_compiler_vendor=`echo $vendor | cut -d: -f1`
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_c_compiler_vendor" >&5
@@ -9835,10 +9902,12 @@
# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
# libraries is broken (non-POSIX).
-# Create a list of thread flags to try. Items starting with a "-" are
-# C compiler flags, and other items are library names, except for "none"
-# which indicates that we try without any flags at all, and "pthread-config"
-# which is a program returning the flags for the Pth emulation library.
+# Create a list of thread flags to try. Items with a "," contain both
+# C compiler flags (before ",") and linker flags (after ","). Other items
+# starting with a "-" are C compiler flags, and remaining items are
+# library names, except for "none" which indicates that we try without
+# any flags at all, and "pthread-config" which is a program returning
+# the flags for the Pth emulation library.
ax_pthread_flags="pthreads none -Kthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
@@ -9914,39 +9983,10 @@
# that too in a future libc.) So we'll check first for the
# standard Solaris way of linking pthreads (-mt -lpthread).
- ax_pthread_flags="-mt,pthread pthread $ax_pthread_flags"
+ ax_pthread_flags="-mt,-lpthread pthread $ax_pthread_flags"
;;
esac
-# GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC)
-
-if test "x$GCC" = "xyes"; then :
- ax_pthread_flags="-pthread -pthreads $ax_pthread_flags"
-fi
-
-# The presence of a feature test macro requesting re-entrant function
-# definitions is, on some systems, a strong hint that pthreads support is
-# correctly enabled
-
-case $host_os in
- darwin* | hpux* | linux* | osf* | solaris*)
- ax_pthread_check_macro="_REENTRANT"
- ;;
-
- aix*)
- ax_pthread_check_macro="_THREAD_SAFE"
- ;;
-
- *)
- ax_pthread_check_macro="--"
- ;;
-esac
-if test "x$ax_pthread_check_macro" = "x--"; then :
- ax_pthread_check_cond=0
-else
- ax_pthread_check_cond="!defined($ax_pthread_check_macro)"
-fi
-
# Are we compiling with Clang?
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC is Clang" >&5
@@ -9978,107 +10018,51 @@
$as_echo "$ax_cv_PTHREAD_CLANG" >&6; }
ax_pthread_clang="$ax_cv_PTHREAD_CLANG"
-ax_pthread_clang_warning=no
-# Clang needs special handling, because older versions handle the -pthread
-# option in a rather... idiosyncratic way
+# GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC)
-if test "x$ax_pthread_clang" = "xyes"; then
+# Note that for GCC and Clang -pthread generally implies -lpthread,
+# except when -nostdlib is passed.
+# This is problematic using libtool to build C++ shared libraries with pthread:
+# [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25460
+# [2] https://bugzilla.redhat.com/show_bug.cgi?id=661333
+# [3] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=468555
+# To solve this, first try -pthread together with -lpthread for GCC
- # Clang takes -pthread; it has never supported any other flag
+if test "x$GCC" = "xyes"; then :
+ ax_pthread_flags="-pthread,-lpthread -pthread -pthreads $ax_pthread_flags"
+fi
- # (Note 1: This will need to be revisited if a system that Clang
- # supports has POSIX threads in a separate library. This tends not
- # to be the way of modern systems, but it's conceivable.)
+# Clang takes -pthread (never supported any other flag), but we'll try with -lpthread first
- # (Note 2: On some systems, notably Darwin, -pthread is not needed
- # to get POSIX threads support; the API is always present and
- # active. We could reasonably leave PTHREAD_CFLAGS empty. But
- # -pthread does define _REENTRANT, and while the Darwin headers
- # ignore this macro, third-party headers might not.)
+if test "x$ax_pthread_clang" = "xyes"; then :
+ ax_pthread_flags="-pthread,-lpthread -pthread"
+fi
- PTHREAD_CFLAGS="-pthread"
- PTHREAD_LIBS=
- ax_pthread_ok=yes
+# The presence of a feature test macro requesting re-entrant function
+# definitions is, on some systems, a strong hint that pthreads support is
+# correctly enabled
- # However, older versions of Clang make a point of warning the user
- # that, in an invocation where only linking and no compilation is
- # taking place, the -pthread option has no effect ("argument unused
- # during compilation"). They expect -pthread to be passed in only
- # when source code is being compiled.
- #
- # Problem is, this is at odds with the way Automake and most other
- # C build frameworks function, which is that the same flags used in
- # compilation (CFLAGS) are also used in linking. Many systems
- # supported by AX_PTHREAD require exactly this for POSIX threads
- # support, and in fact it is often not straightforward to specify a
- # flag that is used only in the compilation phase and not in
- # linking. Such a scenario is extremely rare in practice.
- #
- # Even though use of the -pthread flag in linking would only print
- # a warning, this can be a nuisance for well-run software projects
- # that build with -Werror. So if the active version of Clang has
- # this misfeature, we search for an option to squash it.
+case $host_os in
+ darwin* | hpux* | linux* | osf* | solaris*)
+ ax_pthread_check_macro="_REENTRANT"
+ ;;
- { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether Clang needs flag to prevent \"argument unused\" warning when linking with -pthread" >&5
-$as_echo_n "checking whether Clang needs flag to prevent \"argument unused\" warning when linking with -pthread... " >&6; }
-if ${ax_cv_PTHREAD_CLANG_NO_WARN_FLAG+:} false; then :
- $as_echo_n "(cached) " >&6
+ aix*)
+ ax_pthread_check_macro="_THREAD_SAFE"
+ ;;
+
+ *)
+ ax_pthread_check_macro="--"
+ ;;
+esac
+if test "x$ax_pthread_check_macro" = "x--"; then :
+ ax_pthread_check_cond=0
else
- ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown
- # Create an alternate version of $ac_link that compiles and
- # links in two steps (.c -> .o, .o -> exe) instead of one
- # (.c -> exe), because the warning occurs only in the second
- # step
- ax_pthread_save_ac_link="$ac_link"
- ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
- ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
- ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
- ax_pthread_save_CFLAGS="$CFLAGS"
- for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
- if test "x$ax_pthread_try" = "xunknown"; then :
- break
+ ax_pthread_check_cond="!defined($ax_pthread_check_macro)"
fi
- CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS"
- ac_link="$ax_pthread_save_ac_link"
- cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h. */
-int main(void){return 0;}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
- ac_link="$ax_pthread_2step_ac_link"
- cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h. */
-int main(void){return 0;}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
- break
-fi
-rm -f core conftest.err conftest.$ac_objext \
- conftest$ac_exeext conftest.$ac_ext
-fi
-rm -f core conftest.err conftest.$ac_objext \
- conftest$ac_exeext conftest.$ac_ext
- done
- ac_link="$ax_pthread_save_ac_link"
- CFLAGS="$ax_pthread_save_CFLAGS"
- if test "x$ax_pthread_try" = "x"; then :
- ax_pthread_try=no
-fi
- ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try"
-
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" >&5
-$as_echo "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" >&6; }
-
- case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in
- no | unknown) ;;
- *) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;;
- esac
-
-fi # $ax_pthread_clang = yes
if test "x$ax_pthread_ok" = "xno"; then
for ax_pthread_try_flag in $ax_pthread_flags; do
@@ -10089,11 +10073,11 @@
$as_echo_n "checking whether pthreads work without any flags... " >&6; }
;;
- -mt,pthread)
- { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether pthreads work with -mt -lpthread" >&5
-$as_echo_n "checking whether pthreads work with -mt -lpthread... " >&6; }
- PTHREAD_CFLAGS="-mt"
- PTHREAD_LIBS="-lpthread"
+ *,*)
+ PTHREAD_CFLAGS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\1/"`
+ PTHREAD_LIBS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\2/"`
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether pthreads work with \"$PTHREAD_CFLAGS\" and \"$PTHREAD_LIBS\"" >&5
+$as_echo_n "checking whether pthreads work with \"$PTHREAD_CFLAGS\" and \"$PTHREAD_LIBS\"... " >&6; }
;;
-*)
@@ -10176,7 +10160,13 @@
# if $ax_pthread_check_cond
# error "$ax_pthread_check_macro must be defined"
# endif
- static void routine(void *a) { a = 0; }
+ static void *some_global = NULL;
+ static void routine(void *a)
+ {
+ /* To avoid any unused-parameter or
+ unused-but-set-parameter warning. */
+ some_global = a;
+ }
static void *start_routine(void *a) { return a; }
int
main ()
@@ -10211,6 +10201,104 @@
done
fi
+
+# Clang needs special handling, because older versions handle the -pthread
+# option in a rather... idiosyncratic way
+
+if test "x$ax_pthread_clang" = "xyes"; then
+
+ # Clang takes -pthread; it has never supported any other flag
+
+ # (Note 1: This will need to be revisited if a system that Clang
+ # supports has POSIX threads in a separate library. This tends not
+ # to be the way of modern systems, but it's conceivable.)
+
+ # (Note 2: On some systems, notably Darwin, -pthread is not needed
+ # to get POSIX threads support; the API is always present and
+ # active. We could reasonably leave PTHREAD_CFLAGS empty. But
+ # -pthread does define _REENTRANT, and while the Darwin headers
+ # ignore this macro, third-party headers might not.)
+
+ # However, older versions of Clang make a point of warning the user
+ # that, in an invocation where only linking and no compilation is
+ # taking place, the -pthread option has no effect ("argument unused
+ # during compilation"). They expect -pthread to be passed in only
+ # when source code is being compiled.
+ #
+ # Problem is, this is at odds with the way Automake and most other
+ # C build frameworks function, which is that the same flags used in
+ # compilation (CFLAGS) are also used in linking. Many systems
+ # supported by AX_PTHREAD require exactly this for POSIX threads
+ # support, and in fact it is often not straightforward to specify a
+ # flag that is used only in the compilation phase and not in
+ # linking. Such a scenario is extremely rare in practice.
+ #
+ # Even though use of the -pthread flag in linking would only print
+ # a warning, this can be a nuisance for well-run software projects
+ # that build with -Werror. So if the active version of Clang has
+ # this misfeature, we search for an option to squash it.
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether Clang needs flag to prevent \"argument unused\" warning when linking with -pthread" >&5
+$as_echo_n "checking whether Clang needs flag to prevent \"argument unused\" warning when linking with -pthread... " >&6; }
+if ${ax_cv_PTHREAD_CLANG_NO_WARN_FLAG+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown
+ # Create an alternate version of $ac_link that compiles and
+ # links in two steps (.c -> .o, .o -> exe) instead of one
+ # (.c -> exe), because the warning occurs only in the second
+ # step
+ ax_pthread_save_ac_link="$ac_link"
+ ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
+ ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
+ ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
+ ax_pthread_save_CFLAGS="$CFLAGS"
+ for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
+ if test "x$ax_pthread_try" = "xunknown"; then :
+ break
+fi
+ CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS"
+ ac_link="$ax_pthread_save_ac_link"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+int main(void){return 0;}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ ac_link="$ax_pthread_2step_ac_link"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+int main(void){return 0;}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ break
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+ done
+ ac_link="$ax_pthread_save_ac_link"
+ CFLAGS="$ax_pthread_save_CFLAGS"
+ if test "x$ax_pthread_try" = "x"; then :
+ ax_pthread_try=no
+fi
+ ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try"
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" >&5
+$as_echo "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" >&6; }
+
+ case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in
+ no | unknown) ;;
+ *) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;;
+ esac
+
+fi # $ax_pthread_clang = yes
+
+
+
# Various other checks:
if test "x$ax_pthread_ok" = "xyes"; then
ax_pthread_save_CFLAGS="$CFLAGS"
@@ -10292,6 +10380,7 @@
main ()
{
int i = PTHREAD_PRIO_INHERIT;
+ return i;
;
return 0;
}
@@ -10576,10 +10665,12 @@
# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
# libraries is broken (non-POSIX).
-# Create a list of thread flags to try. Items starting with a "-" are
-# C compiler flags, and other items are library names, except for "none"
-# which indicates that we try without any flags at all, and "pthread-config"
-# which is a program returning the flags for the Pth emulation library.
+# Create a list of thread flags to try. Items with a "," contain both
+# C compiler flags (before ",") and linker flags (after ","). Other items
+# starting with a "-" are C compiler flags, and remaining items are
+# library names, except for "none" which indicates that we try without
+# any flags at all, and "pthread-config" which is a program returning
+# the flags for the Pth emulation library.
ax_pthread_flags="pthreads none -Kthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
@@ -10655,39 +10746,10 @@
# that too in a future libc.) So we'll check first for the
# standard Solaris way of linking pthreads (-mt -lpthread).
- ax_pthread_flags="-mt,pthread pthread $ax_pthread_flags"
+ ax_pthread_flags="-mt,-lpthread pthread $ax_pthread_flags"
;;
esac
-# GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC)
-
-if test "x$GCC" = "xyes"; then :
- ax_pthread_flags="-pthread -pthreads $ax_pthread_flags"
-fi
-
-# The presence of a feature test macro requesting re-entrant function
-# definitions is, on some systems, a strong hint that pthreads support is
-# correctly enabled
-
-case $host_os in
- darwin* | hpux* | linux* | osf* | solaris*)
- ax_pthread_check_macro="_REENTRANT"
- ;;
-
- aix*)
- ax_pthread_check_macro="_THREAD_SAFE"
- ;;
-
- *)
- ax_pthread_check_macro="--"
- ;;
-esac
-if test "x$ax_pthread_check_macro" = "x--"; then :
- ax_pthread_check_cond=0
-else
- ax_pthread_check_cond="!defined($ax_pthread_check_macro)"
-fi
-
# Are we compiling with Clang?
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC is Clang" >&5
@@ -10719,107 +10781,51 @@
$as_echo "$ax_cv_PTHREAD_CLANG" >&6; }
ax_pthread_clang="$ax_cv_PTHREAD_CLANG"
-ax_pthread_clang_warning=no
-# Clang needs special handling, because older versions handle the -pthread
-# option in a rather... idiosyncratic way
+# GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC)
-if test "x$ax_pthread_clang" = "xyes"; then
+# Note that for GCC and Clang -pthread generally implies -lpthread,
+# except when -nostdlib is passed.
+# This is problematic using libtool to build C++ shared libraries with pthread:
+# [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25460
+# [2] https://bugzilla.redhat.com/show_bug.cgi?id=661333
+# [3] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=468555
+# To solve this, first try -pthread together with -lpthread for GCC
- # Clang takes -pthread; it has never supported any other flag
+if test "x$GCC" = "xyes"; then :
+ ax_pthread_flags="-pthread,-lpthread -pthread -pthreads $ax_pthread_flags"
+fi
- # (Note 1: This will need to be revisited if a system that Clang
- # supports has POSIX threads in a separate library. This tends not
- # to be the way of modern systems, but it's conceivable.)
+# Clang takes -pthread (never supported any other flag), but we'll try with -lpthread first
- # (Note 2: On some systems, notably Darwin, -pthread is not needed
- # to get POSIX threads support; the API is always present and
- # active. We could reasonably leave PTHREAD_CFLAGS empty. But
- # -pthread does define _REENTRANT, and while the Darwin headers
- # ignore this macro, third-party headers might not.)
+if test "x$ax_pthread_clang" = "xyes"; then :
+ ax_pthread_flags="-pthread,-lpthread -pthread"
+fi
- PTHREAD_CFLAGS="-pthread"
- PTHREAD_LIBS=
- ax_pthread_ok=yes
+# The presence of a feature test macro requesting re-entrant function
+# definitions is, on some systems, a strong hint that pthreads support is
+# correctly enabled
- # However, older versions of Clang make a point of warning the user
- # that, in an invocation where only linking and no compilation is
- # taking place, the -pthread option has no effect ("argument unused
- # during compilation"). They expect -pthread to be passed in only
- # when source code is being compiled.
- #
- # Problem is, this is at odds with the way Automake and most other
- # C build frameworks function, which is that the same flags used in
- # compilation (CFLAGS) are also used in linking. Many systems
- # supported by AX_PTHREAD require exactly this for POSIX threads
- # support, and in fact it is often not straightforward to specify a
- # flag that is used only in the compilation phase and not in
- # linking. Such a scenario is extremely rare in practice.
- #
- # Even though use of the -pthread flag in linking would only print
- # a warning, this can be a nuisance for well-run software projects
- # that build with -Werror. So if the active version of Clang has
- # this misfeature, we search for an option to squash it.
+case $host_os in
+ darwin* | hpux* | linux* | osf* | solaris*)
+ ax_pthread_check_macro="_REENTRANT"
+ ;;
- { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether Clang needs flag to prevent \"argument unused\" warning when linking with -pthread" >&5
-$as_echo_n "checking whether Clang needs flag to prevent \"argument unused\" warning when linking with -pthread... " >&6; }
-if ${ax_cv_PTHREAD_CLANG_NO_WARN_FLAG+:} false; then :
- $as_echo_n "(cached) " >&6
+ aix*)
+ ax_pthread_check_macro="_THREAD_SAFE"
+ ;;
+
+ *)
+ ax_pthread_check_macro="--"
+ ;;
+esac
+if test "x$ax_pthread_check_macro" = "x--"; then :
+ ax_pthread_check_cond=0
else
- ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown
- # Create an alternate version of $ac_link that compiles and
- # links in two steps (.c -> .o, .o -> exe) instead of one
- # (.c -> exe), because the warning occurs only in the second
- # step
- ax_pthread_save_ac_link="$ac_link"
- ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
- ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
- ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
- ax_pthread_save_CFLAGS="$CFLAGS"
- for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
- if test "x$ax_pthread_try" = "xunknown"; then :
- break
+ ax_pthread_check_cond="!defined($ax_pthread_check_macro)"
fi
- CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS"
- ac_link="$ax_pthread_save_ac_link"
- cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h. */
-int main(void){return 0;}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
- ac_link="$ax_pthread_2step_ac_link"
- cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h. */
-int main(void){return 0;}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
- break
-fi
-rm -f core conftest.err conftest.$ac_objext \
- conftest$ac_exeext conftest.$ac_ext
-fi
-rm -f core conftest.err conftest.$ac_objext \
- conftest$ac_exeext conftest.$ac_ext
- done
- ac_link="$ax_pthread_save_ac_link"
- CFLAGS="$ax_pthread_save_CFLAGS"
- if test "x$ax_pthread_try" = "x"; then :
- ax_pthread_try=no
-fi
- ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try"
-
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" >&5
-$as_echo "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" >&6; }
-
- case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in
- no | unknown) ;;
- *) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;;
- esac
-
-fi # $ax_pthread_clang = yes
if test "x$ax_pthread_ok" = "xno"; then
for ax_pthread_try_flag in $ax_pthread_flags; do
@@ -10830,11 +10836,11 @@
$as_echo_n "checking whether pthreads work without any flags... " >&6; }
;;
- -mt,pthread)
- { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether pthreads work with -mt -lpthread" >&5
-$as_echo_n "checking whether pthreads work with -mt -lpthread... " >&6; }
- PTHREAD_CFLAGS="-mt"
- PTHREAD_LIBS="-lpthread"
+ *,*)
+ PTHREAD_CFLAGS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\1/"`
+ PTHREAD_LIBS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\2/"`
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether pthreads work with \"$PTHREAD_CFLAGS\" and \"$PTHREAD_LIBS\"" >&5
+$as_echo_n "checking whether pthreads work with \"$PTHREAD_CFLAGS\" and \"$PTHREAD_LIBS\"... " >&6; }
;;
-*)
@@ -10917,7 +10923,13 @@
# if $ax_pthread_check_cond
# error "$ax_pthread_check_macro must be defined"
# endif
- static void routine(void *a) { a = 0; }
+ static void *some_global = NULL;
+ static void routine(void *a)
+ {
+ /* To avoid any unused-parameter or
+ unused-but-set-parameter warning. */
+ some_global = a;
+ }
static void *start_routine(void *a) { return a; }
int
main ()
@@ -10952,6 +10964,104 @@
done
fi
+
+# Clang needs special handling, because older versions handle the -pthread
+# option in a rather... idiosyncratic way
+
+if test "x$ax_pthread_clang" = "xyes"; then
+
+ # Clang takes -pthread; it has never supported any other flag
+
+ # (Note 1: This will need to be revisited if a system that Clang
+ # supports has POSIX threads in a separate library. This tends not
+ # to be the way of modern systems, but it's conceivable.)
+
+ # (Note 2: On some systems, notably Darwin, -pthread is not needed
+ # to get POSIX threads support; the API is always present and
+ # active. We could reasonably leave PTHREAD_CFLAGS empty. But
+ # -pthread does define _REENTRANT, and while the Darwin headers
+ # ignore this macro, third-party headers might not.)
+
+ # However, older versions of Clang make a point of warning the user
+ # that, in an invocation where only linking and no compilation is
+ # taking place, the -pthread option has no effect ("argument unused
+ # during compilation"). They expect -pthread to be passed in only
+ # when source code is being compiled.
+ #
+ # Problem is, this is at odds with the way Automake and most other
+ # C build frameworks function, which is that the same flags used in
+ # compilation (CFLAGS) are also used in linking. Many systems
+ # supported by AX_PTHREAD require exactly this for POSIX threads
+ # support, and in fact it is often not straightforward to specify a
+ # flag that is used only in the compilation phase and not in
+ # linking. Such a scenario is extremely rare in practice.
+ #
+ # Even though use of the -pthread flag in linking would only print
+ # a warning, this can be a nuisance for well-run software projects
+ # that build with -Werror. So if the active version of Clang has
+ # this misfeature, we search for an option to squash it.
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether Clang needs flag to prevent \"argument unused\" warning when linking with -pthread" >&5
+$as_echo_n "checking whether Clang needs flag to prevent \"argument unused\" warning when linking with -pthread... " >&6; }
+if ${ax_cv_PTHREAD_CLANG_NO_WARN_FLAG+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown
+ # Create an alternate version of $ac_link that compiles and
+ # links in two steps (.c -> .o, .o -> exe) instead of one
+ # (.c -> exe), because the warning occurs only in the second
+ # step
+ ax_pthread_save_ac_link="$ac_link"
+ ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
+ ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
+ ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
+ ax_pthread_save_CFLAGS="$CFLAGS"
+ for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
+ if test "x$ax_pthread_try" = "xunknown"; then :
+ break
+fi
+ CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS"
+ ac_link="$ax_pthread_save_ac_link"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+int main(void){return 0;}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ ac_link="$ax_pthread_2step_ac_link"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+int main(void){return 0;}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ break
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+ done
+ ac_link="$ax_pthread_save_ac_link"
+ CFLAGS="$ax_pthread_save_CFLAGS"
+ if test "x$ax_pthread_try" = "x"; then :
+ ax_pthread_try=no
+fi
+ ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try"
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" >&5
+$as_echo "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" >&6; }
+
+ case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in
+ no | unknown) ;;
+ *) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;;
+ esac
+
+fi # $ax_pthread_clang = yes
+
+
+
# Various other checks:
if test "x$ax_pthread_ok" = "xyes"; then
ax_pthread_save_CFLAGS="$CFLAGS"
@@ -11033,6 +11143,7 @@
main ()
{
int i = PTHREAD_PRIO_INHERIT;
+ return i;
;
return 0;
}
diff --git a/m4/ax_prepend_flag.m4 b/m4/ax_prepend_flag.m4
new file mode 100644
index 0000000..adac8c5
--- /dev/null
+++ b/m4/ax_prepend_flag.m4
@@ -0,0 +1,51 @@
+# ===========================================================================
+# https://www.gnu.org/software/autoconf-archive/ax_prepend_flag.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+# AX_PREPEND_FLAG(FLAG, [FLAGS-VARIABLE])
+#
+# DESCRIPTION
+#
+# FLAG is added to the front of the FLAGS-VARIABLE shell variable, with a
+# space added in between.
+#
+# If FLAGS-VARIABLE is not specified, the current language's flags (e.g.
+# CFLAGS) is used. FLAGS-VARIABLE is not changed if it already contains
+# FLAG. If FLAGS-VARIABLE is unset in the shell, it is set to exactly
+# FLAG.
+#
+# NOTE: Implementation based on AX_APPEND_FLAG.
+#
+# LICENSE
+#
+# Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
+# Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com>
+# Copyright (c) 2018 John Zaitseff <J.Zaitseff@zap.org.au>
+#
+# Copying and distribution of this file, with or without modification, are
+# permitted in any medium without royalty provided the copyright notice
+# and this notice are preserved. This file is offered as-is, without any
+# warranty.
+
+#serial 2
+
+AC_DEFUN([AX_PREPEND_FLAG],
+[dnl
+AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_SET_IF
+AS_VAR_PUSHDEF([FLAGS], [m4_default($2,_AC_LANG_PREFIX[FLAGS])])
+AS_VAR_SET_IF(FLAGS,[
+ AS_CASE([" AS_VAR_GET(FLAGS) "],
+ [*" $1 "*], [AC_RUN_LOG([: FLAGS already contains $1])],
+ [
+ FLAGS="$1 $FLAGS"
+ AC_RUN_LOG([: FLAGS="$FLAGS"])
+ ])
+ ],
+ [
+ AS_VAR_SET(FLAGS,[$1])
+ AC_RUN_LOG([: FLAGS="$FLAGS"])
+ ])
+AS_VAR_POPDEF([FLAGS])dnl
+])dnl AX_PREPEND_FLAG
