databases/grass7: fix build on 11i386

When I added the option for compiling with openmp, like other ports, I don't use compiler:openmp but directly the default compiler because it works just as well. However, on FreeBSD 11, grass only builds well with LLVM90.

While I'm here I added with-proj-[includes|libs] to be more thorough

Approved by:	tcberner
MFH:		2020Q3
Differential Revision:	https://reviews.freebsd.org/D25712

databases/grass7/Makefile

@@ -39,7 +39,7 @@ LIB_DEPENDS=	libgdal.so:graphics/gdal \
 RUN_DEPENDS=	${PY_NUMPY} \
 		${PYTHON_SITELIBDIR}/six.py:devel/py-six@${PY_FLAVOR}
 
-USES=		blaslapack compiler:c11 gl gmake gnome iconv \
+USES=		blaslapack compiler:features gl gmake gnome iconv \
 		jpeg perl5 pkgconfig python:3.6+ readline shebangfix xorg
 SHEBANG_GLOB=	*.py
 SHEBANG_LANG=	nviz
@@ -65,6 +65,8 @@ CONFIGURE_ARGS=	--with-includes=${LOCALBASE}/include \
 		--enable-largefile \
 		--with-wxwidgets=${WX_CONFIG} \
 		--with-proj-share=${LOCALBASE}/share/proj \
+		--with-proj-includes=${LOCALBASE}/include \
+		--with-proj-libs=${LOCALBASE}/lib \
 		--with-geos=${LOCALBASE}/bin/geos-config \
 		--with-gdal=${LOCALBASE}/bin/gdal-config \
 		--with-pthread=yes \
@@ -135,8 +137,16 @@ ZSTD_LIB_DEPENDS=	libzstd.so:archivers/zstd
 PLIST_SUB+=	WOSBRK="@comment "
 .else
 PLIST_SUB+=	WOSBRK=""
-
 .endif
+
+.if ${ARCH} == "i386" && ${OSVERSION} < 1200000
+# clang 7.x and 8.x do not build properly on 11i386
+CPP=		clang-cpp${LLVM_DEFAULT}
+CC=		clang${LLVM_DEFAULT}
+CXX=		clang++${LLVM_DEFAULT}
+BUILD_DEPENDS+=	clang${LLVM_DEFAULT}:devel/llvm${LLVM_DEFAULT}
+.endif
+
 .if !defined (GRASS_INST_DIR)
 GRASS_INST_DIR=	${PORTNAME}${VER}
 .endif
@@ -144,10 +154,6 @@ GRASS_INST_DIR=	${PORTNAME}${VER}
 MANDIRS=	${PREFIX}/grass${VER}/docs/man/man1
 
 post-patch:
-#	${REINPLACE_CMD} -e \
-#		's|-lblas|${BLASLIB}|g ; \
-#		 s|-llapack|${LAPACKLIB}|g ; \
-#		 s|g2c|f2c|g' ${WRKSRC}/configure
 	${REINPLACE_CMD} -e \
 		's|make -C|$$(MAKE) -C| ; \
 		 /^BINDIR/s|=.*|=	$${DESTDIR}$${UNIX_BIN}| ; \