diff --git a/configure.ac b/configure.ac
index 6a99f3031e2..33c107266a2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -84,10 +84,7 @@ DEFINES=""
 AC_SUBST([DEFINES])
 case "$host_os" in
 *-gnu*)
-if test "x$GCC" = xyes; then
-    DEFINES="$DEFINES -D_POSIX_SOURCE -D_POSIX_C_SOURCE=199309L -D_BSD_SOURCE"
-fi
-    DEFINES="$DEFINES -D_SVID_SOURCE -D_GNU_SOURCE -DPTHREADS"
+    DEFINES="$DEFINES -D_GNU_SOURCE -DPTHREADS"
     ;;
 solaris*)
     DEFINES="$DEFINES -DPTHREADS -DSVR4"