GN: Fix iOS build for BoringSSL

third_party/boringssl/BUILD.gn

 # Copyright 2014 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("//build/config/android/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 
 # Config for us and everybody else depending on BoringSSL.
 config("external_config") {
@@ skipping 45 matching lines @@
     if (current_cpu == "x64") {
       sources = gypi_values.boringssl_win_x86_64_sources
     } else if (current_cpu == "x86") {
       sources = gypi_values.boringssl_win_x86_sources
     }
   }
 } else {
   source_set("boringssl_asm") {
     visibility = [ ":*" ]  # Only targets in this file can depend on this.
 
+    defines = []
     sources = []
     asmflags = []
     include_dirs = [ "src/include" ]
 
     if (current_cpu == "arm" && is_clang) {
       # TODO(hans) Enable integrated-as (crbug.com/124610).
       asmflags += [ "-fno-integrated-as" ]
       if (is_android) {
         rebased_android_toolchain_root =
             rebase_path(android_toolchain_root, root_build_dir)
@@ skipping 111 matching lines @@
 
 fuzzer_test("boringssl_server_fuzzer") {
   sources = [
     "src/fuzz/server.cc",
   ]
   deps = [
     ":boringssl_fuzzer",
   ]
   seed_corpus = "src/fuzz/server_corpus"
 }