Remove dependency on GNU make(1).

It turns out that GNU make(1) is only required because their make(1) spells
target dependencies as $^ while ours use $>.  This change makes the pbzip2's
Makefile both GNU and BSD make(1) friendly at the same time.

This is required to be able to use `archivers/pbzip2' port as a PKG_DEPEND.

Approved by:	farrokhi (maintainer)

archivers/pbzip2/Makefile

@@ -11,12 +11,15 @@ COMMENT=	Parallel BZIP2
 
 LICENSE=	BSD4CLAUSE
 
-USES=		gmake
 MAKE_ARGS=	CFLAGS="${CXXFLAGS}" CC="${CXX}"
 
 PLIST_FILES=	bin/pbzip2 bin/pbunzip2 \
 		man/man1/pbzip2.1.gz man/man1/pbunzip2.1.gz
 
+post-patch:
+# Spell target sources to be understood by both BSD and GNU make(1)
+	@${REINPLACE_CMD} -e 's,$$^,$$>&,' ${WRKSRC}/Makefile
+
 do-install:
 	${INSTALL_PROGRAM} ${WRKSRC}/${PORTNAME} ${STAGEDIR}${PREFIX}/bin/
 	${LN} -sf ${PORTNAME} ${STAGEDIR}${PREFIX}/bin/pbunzip2