Revert of Run pkg-config for Udev only if use_udev==1

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/features.gni")
 import("//build/config/sysroot.gni")
 import("//build/config/ui.gni")
 import("//tools/generate_library_loader/generate_library_loader.gni")
 
@@ skipping 29 matching lines @@
 }
 
 pkg_config("pangocairo") {
   packages = [ "pangocairo" ]
 }
 
 pkg_config("pangoft2") {
   packages = [ "pangoft2" ]
 }
 
-if (use_udev) {
-  pkg_config("udev") {
-    packages = [ "libudev" ]
-  }
+pkg_config("udev") {
+  packages = [ "libudev" ]
 }
 
 # Note: if your target also depends on //dbus, you don't need to add this
 # config (it will get added automatically if you depend on //dbus).
 pkg_config("dbus") {
   packages = [ "dbus-1" ]
 }
 
 pkg_config("gnome_keyring") {
   packages = [ "gnome-keyring-1" ]
@@ skipping 115 matching lines @@
     "pci_alloc",
     "pci_init",
     "pci_cleanup",
     "pci_scan_bus",
     "pci_fill_info",
     "pci_lookup_name",
   ]
 }
 
 # Looking for libspeechd? Use //third_party/speech-dispatcher