[sanitizers] do not add -lclang_rt on mac.

build/config/sanitizers/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/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
 # Contains the dependencies needed for sanitizers to link into executables and
 # shared_libraries. Unconditionally depend upon this target as it is empty if
@@ skipping 169 matching lines @@
       cflags += [
         "-mllvm",
         "-asan-globals=0",
       ]
     } else if (is_mac) {
       # http://crbug.com/352073
       cflags += [
         "-mllvm",
         "-asan-globals=0",
       ]
-      libs = [ "clang_rt.asan_osx_dynamic" ]
-
       # TODO(GYP): deal with mac_bundles.
     } else if (is_win) {
       assert(target_cpu == "x86", "WinASan is 32-bit only currently")
       if (is_component_build) {
         libs = [
           "clang_rt.asan_dynamic-i386.lib",
           "clang_rt.asan_dynamic_runtime_thunk-i386.lib",
         ]
       } else {
         # TODO(rnk): DLLs in the non-component build should link against
@@ skipping 182 matching lines @@
 # This allows to selectively disable ubsan_vptr, when needed. In particular,
 # if some third_party code is required to be compiled without rtti, which
 # is a requirement for ubsan_vptr.
 config("default_sanitizer_flags_but_ubsan_vptr") {
   configs = all_sanitizer_configs - [ ":ubsan_vptr_flags" ]
 }
 
 config("default_sanitizer_flags_but_coverage") {
   configs = all_sanitizer_configs - [ ":coverage_flags" ]
 }