diff --git a/src/configure.ac b/src/configure.ac
index 7f55281..cfc3b1b 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -168,7 +168,7 @@
 if test "`(uname) 2>/dev/null`" = Darwin; then
   AC_MSG_RESULT(yes)
   MACOS_X=yes
-  CPPFLAGS="$CPPFLAGS -D_DARWIN_C_SOURCE -DMACOS_X"
+  CPPFLAGS="$CPPFLAGS -DMACOS_X"
 
   AC_MSG_CHECKING(--disable-darwin argument)
   AC_ARG_ENABLE(darwin,