gn win: Enable exceptions for pdfium build

build/config/win/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/win/visual_studio_version.gni")
 
 # Compiler setup for the Windows SDK. Applied to all targets.
 config("sdk") {
   # The include path is the stuff returned by the script.
   #include_dirs = msvc_config[0]  TODO(brettw) make this work.
@@ skipping 130 matching lines @@
 
 # Some third party code might not compile with WIN32_LEAN_AND_MEAN so we have
 # to have a separate config for it. Remove this config from your target to
 # get the "bloaty and accomodating" version of windows.h.
 config("lean_and_mean") {
   defines = [
     "WIN32_LEAN_AND_MEAN",
   ]
 }
 
-# Nominmax --------------------------------------------------------------------
+# Nominmax ---------------------------------------------------------------------
 
 # Some third party code defines NOMINMAX before including windows.h, which
 # then causes warnings when it's been previously defined on the command line.
 # For such targets, this config can be removed.
 
 config("nominmax") {
   defines = [
     "NOMINMAX",
   ]
 }