r14319 dropped adding -Wwrite-strings to the compile flags.
Add it back in.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14555 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/configure.ac b/configure.ac
index f2872c6..2aeed78 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1656,6 +1656,10 @@
 
 AC_GCC_WARNING_COND([pointer-sign], [HAS_POINTER_SIGN_WARNING])
 AC_GCC_WARNING_COND([write-strings], [HAS_WRITE_STRINGS_WARNING])
+if test $has_warning_flag = yes; then
+  CFLAGS="$CFLAGS -Wwrite-strings"
+  CXXFLAGS="$CXXFLAGS -Wwrite-strings"
+fi
 
 # Convenience function to check whether GCC supports a particular
 # warning option. Similar to AC_GCC_WARNING_COND, but does a