rbcfg: fix format string bug

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@free.fr>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@41410 3c298f89-4303-0410-b956-a3cf2f4a3e73
build: disable the PKG_CHECK_FORMAT_SECURITY check for the failing packages

The idea is to gradually fix the packages

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@free.fr>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@41411 3c298f89-4303-0410-b956-a3cf2f4a3e73
build: Introduce PKG_CHECK_FORMAT_SECURITY

The idea is to get rid of
http://en.wikipedia.org/wiki/Uncontrolled_format_string
by using "-Wformat -Werror=format-security" by default

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@free.fr>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@41412 3c298f89-4303-0410-b956-a3cf2f4a3e73