configure: Include _BSD_SOURCE in standards related defines.

Else, GNU libc does not define strcasecmp() even though it conforms to
POSIX.1-2001.

diff --git a/configure.ac b/configure.ac
index 5cae366f0e47b6d16ee649b491ae17d34a8e7d2c..a5226d278500b27048748ce77fcedbca63faaf99 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -101,6 +101,11 @@ if test "x$enable_standards" = "xyes"; then
        AC_DEFINE([_THREAD_SAFE], 1,
                        [Define to enable reentrant interfaces.])
 
+       dnl GNU libc defines strcasecmp() only when using _BSD_SOURCE even though
+       dnl the function is conforming to POSIX.1-2001 as well. Let's weaken
+       dnl strict standards compliance a bit to work around this.
+       AC_DEFINE([_BSD_SOURCE], 1, [Define to enable 4.3BSD support.])
+
        for flag in -std=c99 -pedantic; do
                AC_MSG_CHECKING([whether $CC accepts $flag])