[Mac/GN] Add a new linker_driver.py option to save unstripped linker output.

build/config/mac/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("//build/config/sysroot.gni")
 import("//build/config/mac/mac_sdk.gni")
 import("//build/config/mac/symbols.gni")
 
 # This is included by reference in the //build/config/compiler config that
 # is applied to all targets. It is here to separate out the logic.
 #
 # This is applied to BOTH desktop Mac and iOS targets.
 config("compiler") {

[brettw, 2016/07/18 19:27:51]

If one always wants this, I'd put the new flag on the "compiler" config here.

[Robert Sesek, 2016/07/18 19:38:48]

Done.

   # These flags are shared between the C compiler and linker.
   common_mac_flags = []
 
   # CPU architecture.
   if (current_cpu == "x64") {
     common_mac_flags += [
       "-arch",
       "x86_64",
     ]
   } else if (current_cpu == "x86") {
@@ skipping 67 matching lines @@
 }
 
 # On Mac, this is used only for executables.
 config("mac_executable_flags") {
   # Remove this when targeting >=10.7 since it is the default in that config.
   ldflags = [ "-Wl,-pie" ]  # Position independent.
 }
 
 # The ldflags referenced below are handled by
 # //build/toolchain/mac/linker_driver.py.
+
 # Remove this config if a target wishes to change the arguments passed to the
 # strip command during linking. This config by default strips all symbols
 # from a binary, but some targets may wish to specify a saves file to preserve
 # specific symbols.
 config("strip_all") {
   if (enable_stripping) {
     ldflags = [ "-Wcrl,strip,-x,-S" ]
   }
 }
+
+# This config will keep unstripped copies of the linker output.
+config("save_unstripped_output") {
+  if (save_unstripped_output) {
+    ldflags = [ "-Wcrl,unstripped," + rebase_path(root_out_dir) ]
+  }
+}