graphics/gexiv2: Use CXXFLAGS instead of CFLAGS

This program uses c++ to build, so it needs to use CXXFLAGS.  While
switching those in order to pick up external c++ flags, relocate the
WRKSRC definition to please portlint.

graphics/gexiv2/Makefile

@@ -7,7 +7,6 @@ PORTREVISION=	4
 CATEGORIES=	graphics
 MASTER_SITES=	http://yorba.org/download/${PORTNAME}/${PORTVERSION:R}/
 DISTNAME=	lib${PORTNAME}_${PORTVERSION}
-WRKSRC=		${WRKDIR}/lib${PORTNAME}-${PORTVERSION}
 
 MAINTAINER=	ports@FreeBSD.org
 COMMENT=	GObject-based wrapper around Exiv2 library
@@ -21,12 +20,15 @@ USES=		gmake libtool:build pkgconfig tar:xz
 USE_GNOME=	glib20 introspection:build
 USE_LDCONFIG=	yes
 MAKE_ARGS=	REQUIRED_CFLAGS="" ENABLE_INTROSPECTION=1
+WRKSRC=		${WRKDIR}/lib${PORTNAME}-${PORTVERSION}
 
 post-patch:
 	@${REINPLACE_CMD} -E \
 		-e 's|^([[:space:]]+)m4[[:space:]]|\1gm4 |' \
 		-e 's|\$$\(LIB\)/pkgconfig|libdata/pkgconfig|' \
-			${WRKSRC}/${MAKEFILE}
+		-e '/^CFLAGS/ s|CFLAGS|CXXFLAGS|' \
+		-e 's|\(CFLAGS\)|(CXXFLAGS)|' \
+		${WRKSRC}/${MAKEFILE}
 
 pre-install:
 	@${MKDIR} ${STAGEDIR}${PREFIX}/share/vala/vapi