third_party: Add libdrm.

third_party/minigbm/BUILD.gn

 # Copyright 2015 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")
 
 assert(is_linux)
 
 declare_args() {
   # Controls whether the build should use the version of minigbm library
   # shipped with the system. In release builds of Chrome OS we use the
   # system version, but when building on dev workstations or the Chrome
   # waterfall we bundle it because Ubuntu doesn't ship a usable version.
   use_system_minigbm = false
 }
 
 if (!use_system_minigbm) {
   config("minigbm_config") {
     include_dirs = [ "src" ]
   }
 
-  pkg_config("libdrm") {
-    packages = [ "libdrm" ]
-  }
-
   shared_library("minigbm") {
     sources = [
       "src/amdgpu.c",
       "src/cirrus.c",
       "src/drv.c",
       "src/evdi.c",
       "src/exynos.c",
       "src/gbm.c",
       "src/gbm_helpers.c",
       "src/gma500.c",
       "src/helpers.c",
       "src/i915.c",
       "src/marvell.c",
       "src/mediatek.c",
       "src/rockchip.c",
       "src/tegra.c",
       "src/udl.c",
       "src/vgem.c",
       "src/virtio_gpu.c",
     ]
 
     configs -= [ "//build/config/compiler:chromium_code" ]
-    configs += [
-      ":libdrm",
-      "//build/config/compiler:no_chromium_code",
+    configs += [ "//build/config/compiler:no_chromium_code" ]
+
+    deps = [
+      "//third_party/libdrm",
     ]
-
     public_configs = [ ":minigbm_config" ]
 
     # Clients need this to pick up the shared library correctly.
     all_dependent_configs =
         [ "//build/config/gcc:rpath_for_built_shared_libraries" ]
   }
 }
 
 if (use_system_minigbm) {
   pkg_config("libgbm") {
     packages = [ "gbm" ]
   }
 
   group("minigbm") {
     public_configs = [ ":libgbm" ]
   }
 }