--- file_not_specified_in_diff	
+++ file_not_specified_in_diff	
@@ -, +, @@ 
--- games-strategy/0ad/0ad-0.0.23b_alpha.ebuild
+++ games-strategy/0ad/0ad-0.0.23b_alpha.ebuild
@@ -18,7 +18,7 @@ 
 LICENSE="GPL-2 LGPL-2.1 MIT CC-BY-SA-3.0 ZLIB"
 SLOT="0"
 KEYWORDS="~amd64 ~x86"
-IUSE="editor +lobby nvtt pch test"
+IUSE="editor +lobby nvtt pch system-mozjs test"
 RESTRICT="test"
 
 RDEPEND="
@@ -42,7 +42,8 @@ 
 	x11-libs/libXcursor
 	editor? ( x11-libs/wxGTK:${WX_GTK_VER}[X,opengl] )
 	lobby? ( >=net-libs/gloox-1.0.20 )
-	nvtt? ( media-gfx/nvidia-texture-tools )"
+	nvtt? ( media-gfx/nvidia-texture-tools )
+	system-mozjs? ( dev-lang/spidermonkey:38 )"
 DEPEND="${RDEPEND}
 	${PYTHON_DEPS}
 	virtual/pkgconfig
@@ -69,6 +70,7 @@ 
 		$(usex test "" "--without-tests")
 		$(usex editor "--atlas" "")
 		$(usex lobby "" "--without-lobby")
+		$(usex system-mozjs "--with-system-mozjs38" "")
 		--collada
 		--bindir="/usr/bin"
 		--libdir="/usr/$(get_libdir)"/${PN}
@@ -101,14 +103,20 @@ 
 	tc-export AR
 
 	# build bundled and patched spidermonkey
-	cd libraries/source/spidermonkey || die
-	JOBS="${MAKEOPTS}" ./build.sh || die
-	cd "${S}" || die
+	if [ ! use system-mozjs ]; then
+		cd libraries/source/spidermonkey || die
+		JOBS="${MAKEOPTS}" ./build.sh || die
+		cd "${S}" || die
+	fi
 
 	# build 3rd party fcollada
 	emake -C libraries/source/fcollada/src
 
 	# build 0ad
+	if [ ! use system-mozjs ]; then
+		CFLAGS="${CFLAGS} -I/usr/include/mozjs-38/"
+		CXXFLAGS="${CXXFLAGS} -I/usr/include/mozjs-38/"
+	fi
 	emake -C build/workspaces/gcc verbose=1
 }
 
@@ -126,7 +134,7 @@ 
 
 	exeinto /usr/$(get_libdir)/${PN}
 	doexe binaries/system/libCollada.so
-	doexe libraries/source/spidermonkey/lib/*.so
+	! use system-mozjs && doexe libraries/source/spidermonkey/lib/*.so
 	use editor && doexe binaries/system/libAtlasUI.so
 
 	dodoc binaries/system/readme.txt