ewah/bitmap: silence warning about MASK macro redefinition
ewah/bitmap: silence warning about MASK macro redefinition

On PowerPC Mac OS X (10.5.8 "Leopard" with Xcode 3.1),
system header /usr/include/ppc/param.h[1] pollutes the
preprocessor namespace with a macro generically named MASK.
This conflicts with the same-named macro in ewah/bitmap.c.
We can avoid this conflict by using a more specific name.

[1]: Included indirectly via:
     git-compat-util.h ->
     sys/sysctl.h ->
     sys/ucred.h ->
     sys/param.h ->
     machine/param.h ->
     ppc/param.h

Signed-off-by: Eric Sunshine <8d6e34f987851aa599257d3831a1af040886842f@sunshineco.com>
Signed-off-by: Jeff King <696e3fbcf235d40b6ea1ebd61c87cbea79d444e7@peff.net>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git