Index: www/mattermost-server/Makefile
===================================================================
--- www/mattermost-server/Makefile	(revision 508920)
+++ www/mattermost-server/Makefile	(working copy)
@@ -16,9 +16,10 @@
 RUN_DEPENDS=	${LOCALBASE}/share/certs/ca-root-nss.crt:security/ca_root_nss \
 		mattermost-webapp>=${PORTVERSION}:www/mattermost-webapp
 
-USES=		go
+USES=		go:modules
 
-GO_LDFLAGS=	-X github.com/mattermost/mattermost-server/model.BuildNumber=${PORTVERSION}
+GO_TARGET=	./cmd/mattermost
+GO_BUILDFLAGS=	-ldflags="-X github.com/mattermost/mattermost-server/model.BuildNumber=${PORTVERSION}"
 
 USE_RC_SUBR=	mattermostd
 
@@ -33,22 +34,11 @@
 USERS=		${MATTERMOSTD_USER}
 GROUPS=		${MATTERMOSTD_GROUP}
 
-pre-build:
-	@${MKDIR} ${WRKSRC}/src/github.com/${GH_ACCOUNT_DEFAULT}/${PORTNAME}
-	@cd ${WRKSRC} && \
-		${MV} api4 app cmd config doc einterfaces imports jobs manualtesting \
-		mlog migrations model plugin services store testlib utils web wsapi vendor \
-		${WRKSRC}/src/github.com/${GH_ACCOUNT_DEFAULT}/${PORTNAME}
-
-do-build:
-	@cd ${WRKSRC}/src/github.com/${GH_ACCOUNT_DEFAULT}/${GH_PROJECT} && \
-		${SETENV} ${MAKE_ENV} GOPATH=${WRKSRC} go install -ldflags="${GO_LDFLAGS}" ./...
-
-do-install:
-	${INSTALL_PROGRAM} ${WRKSRC}/bin/mattermost ${STAGEDIR}${PREFIX}/bin/mattermostd
+post-install:
+	${MV} ${STAGEDIR}${PREFIX}/bin/mattermost ${STAGEDIR}${PREFIX}/bin/mattermostd
 	${MKDIR} ${STAGEDIR}${PREFIX}/etc/mattermost
-	${INSTALL_DATA} ${WRKSRC}/src/github.com/${GH_ACCOUNT_DEFAULT}/${PORTNAME}/config/default.json ${STAGEDIR}${PREFIX}/etc/mattermost/config.json.sample
+	${INSTALL_DATA} ${GO_WRKSRC}/config/default.json ${STAGEDIR}${PREFIX}/etc/mattermost/config.json.sample
 	${MKDIR} ${STAGEDIR}${WWWDIR}
-	cd ${WRKSRC} && ${COPYTREE_SHARE} 'fonts i18n templates' ${STAGEDIR}${WWWDIR}
+	cd ${GO_WRKSRC} && ${COPYTREE_SHARE} 'fonts i18n templates' ${STAGEDIR}${WWWDIR}
 
 .include <bsd.port.mk>