[Mac/GN] Do not use ELF-only cflags on Mac.

build/config/compiler/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/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 1208 matching lines @@
 
       # Set the number of LTCG code-gen threads to eight. The default is four.
       # This gives a 5-10% link speedup.
       "/cgthreads:8",
     ]
     if (full_wpo_on_official) {
       arflags = [ "/LTCG" ]
     }
   }
 } else {
-  common_optimize_on_cflags = [
-    # Don't emit the GCC version ident directives, they just end up in the
-    # .comment section taking up binary size.
-    "-fno-ident",
-
-    # Put data and code in their own sections, so that unused symbols
-    # can be removed at link time with --gc-sections.
-    "-fdata-sections",
-    "-ffunction-sections",
-  ]
+  common_optimize_on_cflags = []
   common_optimize_on_ldflags = []
 
   if (is_android) {
     # We don't omit frame pointers on arm64 since they are required
     # to correctly unwind stackframes which contain system library
     # function frames (crbug.com/391706).
     if (!using_sanitizer && !enable_profiling && current_cpu != "arm64") {
       common_optimize_on_cflags += [ "-fomit-frame-pointer" ]
     }
 
     # TODO(jdduke) Re-enable on mips after resolving linking
     # issues with libc++ (crbug.com/456380).
     if (current_cpu != "mipsel" && current_cpu != "mips64el") {
       common_optimize_on_ldflags += [
         # Warn in case of text relocations.
         "-Wl,--warn-shared-textrel",
       ]
     }
   }
 
   if (is_mac || is_ios) {
     if (symbol_level == 2) {
       # Mac dead code stripping requires symbols.
       common_optimize_on_ldflags += [ "-Wl,-dead_strip" ]
     }
   } else {
-    # Non-Mac Posix linker flags.
+    # Non-Mac Posix flags.
+
+    common_optimize_on_cflags += [
+      # Don't emit the GCC version ident directives, they just end up in the
+      # .comment section taking up binary size.
+      "-fno-ident",
+
+      # Put data and code in their own sections, so that unused symbols
+      # can be removed at link time with --gc-sections.
+      "-fdata-sections",
+      "-ffunction-sections",
+    ]
+
     common_optimize_on_ldflags += [
       # Specifically tell the linker to perform optimizations.
       # See http://lwn.net/Articles/192624/ .
       "-Wl,-O1",
       "-Wl,--gc-sections",
     ]
 
     if (!using_sanitizer) {
       # Functions interposed by the sanitizers can make ld think
       # that some libraries aren't needed when they actually are,
@@ skipping 262 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }