Index: head/Mk/Uses/7z.mk
===================================================================
--- head/Mk/Uses/7z.mk
+++ head/Mk/Uses/7z.mk
@@ -0,0 +1,64 @@
+# $FreeBSD$
+#
+# Extract 7-Zip archives
+#
+# Feature:	7z
+# Usage:	USES=7z or USES=7z:ARGS
+# Valid ARGS:	p7zip, partial
+#
+# p7zip		Extract using 7z(1) instead of bsdtar(1)
+# partial	Extract only files tagged with :7z or in EXTRACT_ONLY_7z
+#
+# MAINTAINER:	jbeich@FreeBSD.org
+
+.if !defined(_INCLUDE_USES_7Z_MK)
+_INCLUDE_USES_7Z_MK=	yes
+
+P7ZIP_CMD?=		7z
+P7ZIP_BEFORE_ARGS?=	x -bd -y -o${P7ZIP_WRKDIR} >/dev/null
+P7ZIP_AFTER_ARGS?=	# empty
+P7ZIP_WRKDIR?=		${EXTRACT_WRKDIR}
+
+.if !empty(7z_ARGS:Np7zip:Npartial)
+IGNORE=			USES=7z has invalid arguments: ${7z_ARGS:Np7zip:Npartial}
+.endif
+
+.if ! ${7z_ARGS:Mp7zip} && (${OPSYS} == FreeBSD && ${OSVERSION} < 1000009)
+# libarchive lacks 7zip reader, fallback to P7ZIP_CMD
+7z_ARGS+=		p7zip
+.endif
+
+.if ${7z_ARGS:Mp7zip}
+EXTRACT_DEPENDS+=	${P7ZIP_CMD}:archivers/p7zip
+.endif
+
+.if ! ${7z_ARGS:Mpartial}
+EXTRACT_SUFX?=		.7z
+.endif
+
+.if ${7z_ARGS:Mp7zip} && ! ${7z_ARGS:Mpartial}
+EXTRACT_CMD?=		${P7ZIP_CMD}
+EXTRACT_BEFORE_ARGS?=	${P7ZIP_BEFORE_ARGS}
+EXTRACT_AFTER_ARGS?=	${P7ZIP_AFTER_ARGS}
+.endif
+
+.if ! ${7z_ARGS:Mp7zip} && ${7z_ARGS:Mpartial} && defined(EXTRACT_ONLY)
+EXTRACT_ONLY+=		${EXTRACT_ONLY_7z}
+.endif
+
+.if ${7z_ARGS:Mp7zip} && ${7z_ARGS:Mpartial}
+EXTRACT_ONLY?=		${DISTFILES:N*\:*7z*:C/:.*//}
+EXTRACT_ONLY_7z?=	${DISTFILES:M*\:*7z*:C/:.*//}
+
+_USES_extract+=		520:do-p7zip-extract
+do-p7zip-extract:
+	@for file in ${EXTRACT_ONLY_7z}; do \
+		if ! ${P7ZIP_CMD} ${P7ZIP_BEFORE_ARGS} \
+			${_DISTDIR}/$$file ${P7ZIP_AFTER_ARGS}; \
+		then \
+			exit 1; \
+		fi; \
+	done
+.endif
+
+.endif