diff --git a/configure.ac b/configure.ac
index 0f732c80..902cce1e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -198,7 +198,7 @@ case "${host}" in
 	have_ld_version_script=yes
         ;;
     *-apple-darwin*)
-        AC_DEFINE(_DARWIN_C_SOURCE, 900000L,
+        AC_DEFINE(_DARWIN_C_SOURCE, 1,
                   Expose all libc features (__DARWIN_C_FULL).)
         AC_DEFINE(_XOPEN_SOURCE, 500, Activate POSIX interface on MacOS X)
         ;;