Eina: Set EINA_CFLAGS/EINA_LDFLAGS before looking for system headers

Eina: Set EINA_CFLAGS/EINA_LDFLAGS before looking for system headers
We must check for cflags/ldflags and evil/escape libs before looking
for headers (like sys/mman.h) because they could be provided by one
of those libs. We must also set CFLAGS/LDFLAGS/LIBS variables to the
EINA_CFLAGS/EINA_LDFLAGS/EINA_LIBS vars so they get picked up properly

git-svn-id: http://svn.enlightenment.org/svn/e/trunk/eina@66954 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33