Allow usage of kernel headers

And build libraries with CLANG

Change-Id: I9fa11bd72fa632551679d8b13a89cccbaae53e77
Signed-off-by: helicopter88 <johnlemon.lol@gmail.com>

Conflicts:
	libcopybit/Android.mk
	libexternal/Android.mk
	libgenlock/Android.mk
	libgralloc/Android.mk
	libhwcomposer/Android.mk
	liboverlay/Android.mk
	libqdutils/Android.mk
	libqservice/Android.mk