--- /usr/portage/dev-libs/libnsfb/libnsfb-0.0.2.ebuild	2012-07-18 18:00:36.000000000 +0200
+++ libnsfb-0.0.2.ebuild	2013-02-17 15:14:48.813396377 +0100
@@ -13,14 +13,11 @@
 LICENSE="MIT"
 SLOT="0"
 KEYWORDS="~amd64 ~arm"
-IUSE="static-libs"
+IUSE="static-libs vnc sdl xcb"
 
-RDEPEND="media-libs/libsdl
-	net-libs/libvncserver
-	x11-libs/libxcb
-	x11-libs/xcb-util
-	x11-libs/xcb-util-image
-	x11-libs/xcb-util-keysyms"
+RDEPEND="sdl? ( media-libs/libsdl )
+	vnc? ( net-libs/libvncserver )
+	xcb? ( x11-libs/libxcb x11-libs/xcb-util x11-libs/xcb-util-image x11-libs/xcb-util-keysyms )"
 DEPEND="${RDEPEND}
 	virtual/pkgconfig"
 
@@ -44,6 +41,15 @@
 	echo "Q := " >> Makefile.config.override
 	echo "CC := $(tc-getCC)" >> Makefile.config.override
 	echo "AR := $(tc-getAR)" >> Makefile.config.override
+
+	# replace auto-detection by USE flags for sdl, vnc, and xcb
+	local u a=available n=NSFB_
+	for u in VNC SDL XCB
+	do
+		use ${u,,} && eval $u=yes
+		sed -e "/$a,$n$u/s+\(^.*$\)+#\1\n$n${u}_${a^^} := ${!u:-no}+" \
+			-i Makefile || die
+	done
 }
 
 src_compile() {