Add a switch to choose between graphics/giflib and graphics/libungif
as GIF implementation. They are src/binary compatible and mutually
exclusive, so this is a global choice.
Up to now, "libungif" is used by pkgs, due to patent problems. The
patents are said to be expired, and "giflib" gets somewhat better
maintainance upstream these days, so set the new default to "giflib".


(drochner)

# $NetBSD: giflib.buildlink3.mk,v 1.1 2011/03/09 16:22:01 drochner Exp $

# choose a GIF library implemtation:
# "libungif" was used to avoid patent problems. The patents are
# expired, so "giflib" should be safe to use.

.if !defined(MK_GIFLIB_BUILDLINK3_MK)
MK_GIFLIB_BUILDLINK3_MK=	#defined

.include "../../mk/bsd.prefs.mk"
GIFLIB_IMPLEMENTATION?= giflib
BUILD_DEFS+=	GIFLIB_IMPLEMENTATION

.if ${GIFLIB_IMPLEMENTATION} == "giflib"
.  include "../../graphics/giflib/buildlink3.mk"
.elif ${GIFLIB_IMPLEMENTATION} == "libungif"
.  include "../../graphics/libungif/buildlink3.mk"
.else
PKG_FAIL_REASON= \
	"\"${GIFLIB_IMPLEMENTATION}\" is invalid giflib in ${PKGNAME}."
.endif

.endif #MK_GIFLIB_BUILDLINK3_MK