Fix help and error messages.

tools/gn/setup.cc

 // 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.
 
 #include "tools/gn/setup.h"
 
 #include <stdlib.h>
 
 #include <algorithm>
 
@@ skipping 40 matching lines @@
     "      the build file execution environment for each toolchain.\n"
     "\n"
     "  secondary_source [optional]\n"
     "      Label of an alternate directory tree to find input files. When\n"
     "      searching for a BUILD.gn file (or the build config file discussed\n"
     "      above), the file fill first be looked for in the source root.\n"
     "      If it's not found, the secondary source root will be checked\n"
     "      (which would contain a parallel directory hierarchy).\n"
     "\n"
     "      This behavior is intended to be used when BUILD.gn files can't be\n"
-    "      checked in to certain source directories for whaever reason.\n"
+    "      checked in to certain source directories for whatever reason.\n"
     "\n"
     "      The secondary source root must be inside the main source tree.\n"
     "\n"
     "Example .gn file contents\n"
     "\n"
     "  buildconfig = \"//build/config/BUILDCONFIG.gn\"\n"
     "\n"
     "  secondary_source = \"//build/config/temporary_buildfiles/\"\n";
 
 namespace {
@@ skipping 354 matching lines @@
 }
 
 void DependentSetup::RunPreMessageLoop() {
   CommonSetup::RunPreMessageLoop();
 }
 
 bool DependentSetup::RunPostMessageLoop() {
   return CommonSetup::RunPostMessageLoop();
 }