buildroot

libsepol: add patch to make the build process more standard

Patch the Makefiles to make PREFIX and DESTDIR follow standard
semantics to get rid of DESTDIR during compile time in
libsepol.mk and generate proper pkg-config files.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>