Build fixes for fnl/musl

third_party/libevent/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.
 
 source_set("libevent") {
   sources = [
     "buffer.c",
     "evbuffer.c",
     "evdns.c",
     "event.c",
@@ skipping 15 matching lines @@
     include_dirs = [ "mac" ]
   } else if (is_linux) {
     sources += [ "epoll.c" ]
     include_dirs = [ "linux" ]
     libs = [ "rt" ]
   } else if (is_android) {
     sources += [ "epoll.c" ]
     include_dirs = [ "android" ]
   }
 
+  if (is_fnl) {
+    include_dirs += [ "compat" ]
+  }
+
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
 }