Minor fixes for the GN Windows build.

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")
 if (cpu_arch == "arm") {
   import("//build/config/arm.gni")
 }
 if (is_posix) {
   import("//build/config/gcc/gcc_version.gni")
 }
 
 declare_args() {
   # Normally, Android builds are lightly optimized, even for debug builds, to
   # keep binary size down. Setting this flag to true disables such optimization
   android_full_debug = false
 }
 
 use_gold = is_linux && cpu_arch == "x64"
 
-# linux_use_debug_fission: whether to use split DWARF debug info
-# files. This can reduce link time significantly, but is incompatible
-# with some utilities such as icecc and ccache. Requires gold and
-# gcc >= 4.8 or clang.
-# http://gcc.gnu.org/wiki/DebugFission
-#
-# TODO(GYP) enable this. Currently this gives errors from objcopy, presumably
-# because some other symbol or toolchain setting isn't correct.
-#use_debug_fission = use_gold
-use_debug_fission = false
+if (!is_win) {
+  # linux_use_debug_fission: whether to use split DWARF debug info
+  # files. This can reduce link time significantly, but is incompatible
+  # with some utilities such as icecc and ccache. Requires gold and
+  # gcc >= 4.8 or clang.
+  # http://gcc.gnu.org/wiki/DebugFission
+  #
+  # TODO(GYP) enable this. Currently this gives errors from objcopy, presumably
+  # because some other symbol or toolchain setting isn't correct.
+  #use_debug_fission = use_gold
+  use_debug_fission = false
+}
 
 # default_include_dirs ---------------------------------------------------------
 #
 # This is a separate config so that third_party code (which would not use the
 # source root and might have conflicting versions of some headers) can remove
 # this and specify their own include paths.
 config("default_include_dirs") {
   include_dirs = [
     "//",
     root_gen_dir,
@@ skipping 867 matching lines @@
       cflags += [ "-gsplit-dwarf" ]
     }
   }
 }
 
 config("no_symbols") {
   if (!is_win) {
     cflags = [ "-g0" ]
   }
 }