Support building BoringSSL with NSS certificates.

build/linux/system.gyp

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'conditions': [
       ['sysroot!=""', {
         'pkg-config': '<(chroot_cmd) ./pkg-config-wrapper "<(sysroot)" "<(target_arch)" "<(system_libdir)"',
       }, {
@@ skipping 1137 matching lines @@
     {
       'target_name': 'ssl',
       'type': 'none',
       'conditions': [
         ['_toolset=="target"', {
           'conditions': [
             ['use_openssl==1', {
               'dependencies': [
                 '../../third_party/boringssl/boringssl.gyp:boringssl',
               ],
-            }],
-            ['use_openssl==0', {
+            }, {
               'dependencies': [
                 '../../net/third_party/nss/ssl.gyp:libssl',
               ],
               'direct_dependent_settings': {
                 'include_dirs+': [
                   # We need for our local copies of the libssl3 headers to come
                   # before other includes, as we are shadowing system headers.
                   '<(DEPTH)/net/third_party/nss/ssl',
                 ],
+              },
+            }],
+            ['use_openssl==0 or use_nss==1', {

[Ryan Sleevi, 2015/02/23 20:37:40]

I am _deeply_ confused by these GYP variables, between system.gyp and
common.gypi

Could you document more _in the file_ what they mean and how they're set?

+              'direct_dependent_settings': {
                 'cflags': [
                   '<!@(<(pkg-config) --cflags nss)',
                 ],
               },
               'link_settings': {
                 'ldflags': [
                   '<!@(<(pkg-config) --libs-only-L --libs-only-other nss)',
                 ],
                 'libraries': [
                   '<!@(<(pkg-config) --libs-only-l nss | sed -e "s/-lssl3//")',
                 ],
               },
             }],
-            ['use_openssl==0 and clang==1', {
+            ['(use_openssl==0 or use_nss==1) and clang==1', {
               'direct_dependent_settings': {
                 'cflags': [
                   # There is a broken header guard in /usr/include/nss/secmod.h:
                   # https://bugzilla.mozilla.org/show_bug.cgi?id=884072
                   '-Wno-header-guard',
                 ],
               },
             }],
           ]
         }],
       ],
     },
   ],
 }