Support building BoringSSL with NSS certificates.

crypto/crypto.gyp

Index: crypto/crypto.gyp
diff --git a/crypto/crypto.gyp b/crypto/crypto.gyp
index 6d60f480fedeb46f2709086c502b4f239ef8ed48..72de9357007b51ad5549b0a4bae397be0e7701e2 100644
--- a/crypto/crypto.gyp
+++ b/crypto/crypto.gyp
@@ -108,9 +108,6 @@
               'ec_signature_creator_nss.cc',
               'encryptor_nss.cc',
               'hmac_nss.cc',
-              'nss_util.cc',
-              'nss_util.h',
-              'nss_util_internal.h',
               'rsa_private_key_nss.cc',
               'secure_hash_default.cc',
               'signature_creator_nss.cc',
@@ -143,6 +140,13 @@
               'symmetric_key_openssl.cc',
             ],
         },],
+        [ 'use_openssl==1 and use_nss==0', {
+            'sources!': [
+              'nss_util.cc',
+              'nss_util.h',
+              'nss_util_internal.h',
+            ],
+        },],
       ],
       'sources': [
         '<@(crypto_sources)',
@@ -182,7 +186,7 @@
         '../testing/gtest.gyp:gtest',
       ],
       'conditions': [
-        [ 'os_posix == 1 and OS != "mac" and OS != "android" and OS != "ios"', {
+        [ 'use_nss == 1', {
           'conditions': [
             [ 'use_allocator!="none"', {
                 'dependencies': [
@@ -194,7 +198,12 @@
           'dependencies': [
             '../build/linux/system.gyp:ssl',
           ],
-        }, {  # os_posix != 1 or OS == "mac" or OS == "android" or OS == "ios"
+        }, {  # use_nss != 1
+          'sources!': [
+            'nss_util_unittest.cc',
+          ]
+        }],
+        [ 'use_openssl == 1 or use_nss == 0', {
           'sources!': [
             'rsa_private_key_nss_unittest.cc',
           ]
@@ -212,10 +221,6 @@
           'dependencies': [
             '../third_party/boringssl/boringssl.gyp:boringssl',
           ],
-          'sources!': [
-            'nss_util_unittest.cc',
-            'rsa_private_key_nss_unittest.cc',
-          ],
         }, {
           'sources!': [
             'openssl_bio_string_unittest.cc',