* grobian@gentoo.org: allow compilation on non glibc hosts by use of an
                      external library for argp, and check for certain
                      headers before including them

--- configure.ac
+++ configure.ac
@@ -14,7 +14,7 @@
 
 # Checks for header files.
 AC_HEADER_STDC
-AC_CHECK_HEADERS([limits.h stdlib.h string.h unistd.h])
+AC_CHECK_HEADERS([limits.h stdlib.h string.h unistd.h error.h])
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
@@ -24,6 +24,7 @@
 AC_FUNC_MALLOC
 AC_FUNC_REALLOC
 AC_CHECK_FUNCS([atexit realpath setenv strchr])
+AC_SEARCH_LIBS([argp_usage], [argp])
 
 AC_CONFIG_FILES([Makefile
                  src/Makefile])
--- src/unrar.c
+++ src/unrar.c
@@ -24,7 +24,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
+#ifdef HAVE_ERROR_H
 #include <error.h>
+#endif
 #include <errno.h>
 #include <sys/stat.h>
 #include <sys/types.h>
--- src/opts.c
+++ src/opts.c
@@ -22,7 +22,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#ifdef HAVE_ERROR_H
 #include <error.h>
+#endif
 #include <argp.h>
 #include <unistd.h>
 #include <sys/types.h>
--- src/opts.h
+++ src/opts.h
@@ -56,4 +56,13 @@
 int parse_opts (int argc, char **argv, struct arguments_t *arguments);
 int compat_parse_opts (int argc, char **argv, struct arguments_t *arguments);
 
+#ifndef HAVE_ERROR_H
+#define error(S, E, ...) \
+	fflush(stdout); \
+	fprintf(stderr, "unrar: " __VA_ARGS__); \
+	if (E != 0) fprintf(stderr, ": %s", strerror(E)); \
+	fprintf(stderr, "\n"); \
+	if (S != 0) exit(S);
+#endif
+
 #endif