Explicitly don't support the make gyp generator.

build/gyp_chromium

 #!/usr/bin/env python
 
 # Copyright (c) 2012 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.
 
 # This script is wrapper for Chromium that adds some support for how GYP
 # is invoked by Chromium beyond what can be done in the gclient hooks.
 
 import glob
@@ skipping 436 matching lines @@
   # currently exist.  The check for circular dependencies is currently
   # bypassed on other platforms, but is left enabled on the Mac, where a
   # violation of the rule causes Xcode to misbehave badly.
   # TODO(mark): Find and kill remaining circular dependencies, and remove this
   # option.  http://crbug.com/35878.
   # TODO(tc): Fix circular dependencies in ChromiumOS then add linux2 to the
   # list.
   if sys.platform not in ('darwin',):
     args.append('--no-circular-check')
 
+  # We explicitly don't support the make gyp generator (crbug.com/348686). Be
+  # nice and fail here, rather than choking in gyp.
+  if 'make' in os.environ.get('GYP_GENERATORS', ''):
+    print 'Error: make gyp generator not supported (check GYP_GENERATORS).'
+    sys.exit(1)
+
   # Default to ninja on linux and windows, but only if no generator has
   # explicitly been set.
   # Also default to ninja on mac, but only when not building chrome/ios.
   # . -f / --format has precedence over the env var, no need to check for it
   # . set the env var only if it hasn't been set yet
   # . chromium.gyp_env has been applied to os.environ at this point already
   if sys.platform.startswith('linux') and not os.environ.get('GYP_GENERATORS'):
     os.environ['GYP_GENERATORS'] = 'ninja'
   if sys.platform.startswith('win') and not os.environ.get('GYP_GENERATORS'):
     os.environ['GYP_GENERATORS'] = 'ninja'
@@ skipping 88 matching lines @@
   print 'Running build/landmines.py...'
   subprocess.check_call(
       [sys.executable, os.path.join(script_dir, 'landmines.py')])
 
   if vs2013_runtime_dll_dirs:
     x64_runtime, x86_runtime = vs2013_runtime_dll_dirs
     CopyVsRuntimeDlls(os.path.join(chrome_src, GetOutputDirectory()),
                       (x86_runtime, x64_runtime))
 
   sys.exit(gyp_rc)