. Make the dependency on cairo optional.

. Make the dependency on X11 an actual option.

PR:		147679
Submitted by:	Dmitry <dmitry2006@yandex.ru>

math/gnuplot/Makefile

@@ -13,35 +13,34 @@ MASTER_SITES=	SF
 MAINTAINER=	glewis@FreeBSD.org
 COMMENT=	A command-driven interactive function plotting program
 
-LIB_DEPENDS=	cairo.2:${PORTSDIR}/graphics/cairo
-
 GNU_CONFIGURE=	yes
 CONFIGURE_ARGS+=--with-lasergnu \
 		--with-readline=gnu \
 		--without-linux-vga \
 		--without-lisp-files \
 		--without-tutorial
-USE_GNOME=	pango
 
-OPTIONS=	GD		"Enable GD support"		on \
+OPTIONS=	X11		"Enable X11 support"		on \
+		GD		"Enable GD support"		on \
 		GRIDBOX		"Use the gridbox optimization for hidden3d" off \
 		PDF		"Enable PDF support"		on \
 		PLOT		"Enable plot support"		on \
 		TETEX		"Search kpsexpand at run-time"	on \
 		THINSPLINES	"Enable thin plate splines for grids in dgrid3d" off \
-		WX		"Enable WX support"		on
+		WX		"Enable WX support"		on \
+		CAIRO		"Enable CAIRO support"		on
 
 MAN1=		gnuplot.1 lasergnu.1
 INFO=		gnuplot
 
 .include <bsd.port.options.mk>
 
-.if !defined(WITHOUT_X11)
-USE_XORG=		x11
-PLIST_SUB+=		X11=""
-.else
+.if defined(WITHOUT_X11)
 CONFIGURE_ARGS+=	--without-x
 PLIST_SUB+=		X11="@comment "
+.else
+USE_XORG=		x11
+PLIST_SUB+=		X11=""
 .endif
 
 .if defined(WITHOUT_GD)
@@ -92,6 +91,13 @@ USE_WX=			2.4+
 WX_CONF_ARGS=		absolute
 .endif
 
+.if defined(WITHOUT_CAIRO)
+CONFIGURE_ARGS+=	--without-cairo
+.else
+LIB_DEPENDS+=		cairo.2:${PORTSDIR}/graphics/cairo
+USE_GNOME+=		pango
+.endif
+
 post-patch:
 .if defined(WITHOUT_TETEX)
 	@${REINPLACE_CMD} -e \