package/vlc: backport upstream patches to fix compat function for static_assert

Fixes
http://autobuild.buildroot.net/results/3b9/3b9d15f226057706c185270788050dace7b7b535/



Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>