Enable timerfd in libusb.

third_party/libusb/BUILD.gn

 # Copyright 2014 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.
 
 assert(!is_android && !is_ios)
 
 import("//build/config/features.gni")
 
 config("libusb_config") {
   include_dirs = [ "src/libusb" ]
@@ skipping 77 matching lines @@
     ]
   }
 
   if (is_linux) {
     sources += [
       "src/libusb/os/linux_usbfs.c",
       "src/libusb/os/linux_usbfs.h",
     ]
     defines += [
       "OS_LINUX=1",
+      "USBI_TIMERFD_AVAILABLE",
       "_GNU_SOURCE=1",
     ]
   }
 
   if (use_udev) {
     sources += [ "src/libusb/os/linux_udev.cc" ]
     defines += [
       "HAVE_LIBUDEV=1",
       "USE_UDEV=1",
     ]
@@ skipping 21 matching lines @@
       "src/libusb/os/threads_windows.h",
       "src/libusb/os/windows_common.h",
       "src/libusb/os/windows_usb.c",
       "src/libusb/os/windows_usb.h",
       "src/msvc/config.h",
       "src/msvc/inttypes.h",
       "src/msvc/stdint.h",
     ]
   }
 }