Add -Wformat-nonliteral -Wformat-security
And fix the resulting compile failures.
I'm sorry about the patch necessary to gstclockoverlay.h but after
talking to Tim we decided we can live with it.
diff --git a/configure.ac b/configure.ac
index cdac02c..11610d5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -308,10 +308,11 @@
AG_GST_SET_PLUGINDIR
dnl define an ERROR_CFLAGS Makefile variable
-AG_GST_SET_ERROR_CFLAGS($GST_GIT, [-Wmissing-declarations -Wmissing-prototypes -Wredundant-decls -Wundef -Wwrite-strings])
+dnl -Wformat-nonliteral - see ext/pango/gstclockoverlay.c and http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39438
+AG_GST_SET_ERROR_CFLAGS($GST_GIT, [-Wmissing-declarations -Wmissing-prototypes -Wredundant-decls -Wundef -Wwrite-strings -Wformat-nonliteral -Wformat-security])
dnl define an ERROR_CXXFLAGS Makefile variable
-AG_GST_SET_ERROR_CXXFLAGS($GST_GIT, [-Wmissing-declarations -Wmissing-prototypes -Wredundant-decls -Wundef -Wwrite-strings])
+AG_GST_SET_ERROR_CXXFLAGS($GST_GIT, [-Wmissing-declarations -Wmissing-prototypes -Wredundant-decls -Wundef -Wwrite-strings -Wformat-nonliteral -Wformat-security])
dnl define correct level for debugging messages
AG_GST_SET_LEVEL_DEFAULT($GST_GIT)
