[rhythmbox] add -Wformat-security to WARN_CFLAGS where available

[Jonathan Matthew <jmatthew src gnome org>]

commit aac32649cf45439dd73a415e7551ab1eacfb19c7
Author: Jonathan Matthew <jonathan d14n org>
Date:   Tue Feb 28 07:48:14 2012 +1000

    add -Wformat-security to WARN_CFLAGS where available

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 0a8f48b..da9d25c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -538,7 +538,7 @@ if test "$GCC" = "yes" -a "$set_more_warnings" != "no"; then
 	-Wunused-label -Wunused-value \
 	-Wchar-subscripts -Wmissing-declarations -Wmissing-prototypes \
 	-Wnested-externs -Wpointer-arith \
-	-Wcast-align -Wall \
+	-Wcast-align -Wformat-security -Wall \
 	-Werror -std=gnu89"
 
 	if echo "$CFLAGS" | grep -q -- '-O' && echo "$CFLAGS" | grep -q -v -- '-O0'; then