Index: Makefile
===================================================================
--- Makefile	(revision 506540)
+++ Makefile	(working copy)
@@ -15,7 +15,7 @@
 
 RUN_DEPENDS=	gpu-firmware-kmod>=g20180319:graphics/gpu-firmware-kmod
 
-USES=		kmod uidfix
+USES=		compiler kmod uidfix
 
 OPTIONS_DEFINE=	DEBUG
 
@@ -29,7 +29,7 @@
 GH_PROJECT=	drm-legacy
 GH_TAGNAME=	990f64b
 
-.include <bsd.port.options.mk>
+.include <bsd.port.pre.mk>
 
 .if ${ARCH} == amd64 || ${ARCH} == i386
 PLIST_SUB+=	X86=""
@@ -37,6 +37,10 @@
 PLIST_SUB+=	X86="@comment "
 .endif
 
+.if ${CHOSEN_COMPILER_TYPE} == clang && ${COMPILER_VERSION} > 70
+CFLAGS+=	-Wno-error=pointer-sign
+.endif
+
 .if ${OPSYS} == FreeBSD && ${OSVERSION} < 1200080
 IGNORE=		only for 12.0 or higher after removal of base components
 .endif
@@ -44,4 +48,4 @@
 IGNORE=		not supported on anything but FreeBSD
 .endif
 
-.include <bsd.port.mk>
+.include <bsd.port.post.mk>