Add GN buildfile for gfx

build/config/linux/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/linux/pkg_config.gni")
 import("//build/config/sysroot.gni")
 
 config("sdk") {
   if (sysroot != "") {
     cflags = [ "--sysroot=" + sysroot ]
@@ skipping 11 matching lines @@
 config("executable_ldconfig") {
   ldflags = [
     # Want to pass "\$". Need to escape both '\' and '$'. GN will re-escape as
     # required for ninja.
     "-Wl,-rpath=\\\$ORIGIN/lib/",
 
     "-Wl,-rpath-link=lib/",
   ]
 }
 
+pkg_config("dridrm") {
+  packages = [ "libdrm" ]
+}
+
 config("fontconfig") {
   libs = [ "fontconfig" ]
 }
 
 pkg_config("freetype2") {
   packages = [ "freetype2" ]
 }
 
 pkg_config("glib") {
   packages = [ "glib-2.0", "gmodule-2.0", "gobject-2.0", "gthread-2.0" ]
@@ skipping 22 matching lines @@
     "Xcursor",
     "Xdamage",
     "Xext",
     "Xfixes",
     "Xi",
     "Xrender",
     "Xss",
     "Xtst",
   ]
 }