Convert GN single-item list concat to use lists.

tools/gn/secondary/crypto/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.
 
 import("ssl/flags.gni")
 
 crypto_minimal_sources = [
   "hmac.cc",
   "hmac.h",
   "hmac_win.cc",
@@ skipping 119 matching lines @@
     ]
   }
   if (!is_win) {
     sources -= [
       "capi_util.cc",
       "capi_util.h",
     ]
   }
 
   if (use_nss) {
-    configs += "//third_party/nss:nss_linux_config"
+    configs += [ "//third_party/nss:nss_linux_config" ]
   } else {
     sources -= [
       "ec_private_key_nss.cc",
       "ec_signature_creator_nss.cc",
       "encryptor_nss.cc",
       "hmac_nss.cc",
       "nss_util.cc",
       "nss_util.h",
       "rsa_private_key_nss.cc",
       "secure_hash_default.cc",
@@ skipping 85 matching lines @@
     "//base/test:run_all_unittests",
     "//base/test:test_support_base",
     "//testing/gmock",
     "//testing/gtest",
   ]
 
   if (is_mac) {
     #deps += "//third_party/nss:nspr"
   }
 }