Suppress -Wunused-function for nss.

nss.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': [
       ['OS=="ios"', {
         'exclude_nss_root_certs%': 0,
         'exclude_nss_libpkix%': 0,
@@ skipping 1123 matching lines @@
               # nss doesn't explicitly cast between different enum types.
               '-Wno-conversion',
               # nss passes "const char*" through "void*".
               '-Wno-incompatible-pointer-types',
               # nss prefers `a && b || c` over `(a && b) || c`.
               '-Wno-logical-op-parentheses',
               # nss doesn't use exhaustive switches on enums
               '-Wno-switch',
               # nss has some `unsigned < 0` checks.
               '-Wno-tautological-compare',
+              # nss-urandom-abort.patch removed the only call to
+              # rng_systemFromNoise
+              '-Wno-unused-function',
             ],
           },
           'conditions': [
             ['exclude_nss_root_certs==1', {
               'defines': [
                 'NSS_DISABLE_ROOT_CERTS',
               ],
             }],
             ['exclude_nss_libpkix==1', {
               'defines': [
@@ skipping 134 matching lines @@
                 # mpi_x86_asm.c contains MSVC inline assembly code.
                 'nss/lib/freebl/mpi/mpi_x86_asm.c',
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }