Implement net in GN build.

net/third_party/nss/ssl/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.
 
 config("ssl_config") {
   include_dirs = [ "." ]
 
   if (is_mac || is_win) {
     defines = [ "NSS_PLATFORM_CLIENT_AUTH" ]
   }
@@ skipping 39 matching lines @@
     "sslt.h",
     "ssltrace.c",
     "sslver.c",
     "unix_err.c",
     "unix_err.h",
     "win32err.c",
     "win32err.h",
     "bodge/secitem_array.c",
   ]
 
-  direct_dependent_settings = [ ":ssl_config" ]
+  direct_dependent_configs = [ ":ssl_config" ]
 
   cflags = []
   defines = [
     "NO_PKCS11_BYPASS",
     "NSS_ENABLE_ECC",
     "USE_UTIL_DIRECTLY",
   ]
 
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
 
   if (is_win) {
     cflags += [ "/wd4267" ]  # Disable warning: Conversion from size_t to 'type'.
 
     sources -= [
       "unix_err.c",
       "unix_err.h",
     ]
     sources += [ "exports_win.def" ]
   } else if (is_linux) {
     #visibility hidden thing.
     libs = [ "dl" ]
 
     include_dirs = [ "bodge" ]
 
-    direct_dependent_configs = [
+    # Must be after ssl_config since we want our SSL headers to take
+    # precedence.
+    direct_dependent_configs += [
       "//third_party/nss:system_nss_no_ssl_config"
     ]
   } else if (is_mac) {
     libs = [ "Security.framework" ]
   }
 
   if (is_posix) {
     sources -= [
       "win32err.c",
       "win32err.h",
@@ skipping 32 matching lines @@
       # There is a broken header guard in /usr/include/nss/secmod.h:
       # https://bugzilla.mozilla.org/show_bug.cgi?id=884072
       "-Wno-header-guard",
     ]
   }
 
   if (is_debug) {
     defines += [ "DEBUG" ]
   }
 }