diff --git a/configure.ac b/configure.ac
index b74fbf9b0..d30e89229 100644
--- a/configure.ac
+++ b/configure.ac
@@ -748,6 +748,12 @@ case "$host_os" in
 		enable_osx=yes ;;
 esac
 
+case "$host_os" in
+	darwin10*)
+		CFLAGS="$CFLAGS -isysroot /Developer/SDKs/MacOSX10.5.sdk"
+		;;
+esac
+
 AM_CONDITIONAL(HAVE_OSX, test x$enable_osx = xyes)
 
 AC_ARG_ENABLE(shout,