Add a variable use_system_xcode to GN.

third_party/WebKit/Source/build/scripts/rule_bison.py

 #!/usr/bin/python
 #
 # Copyright (C) 2009 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
@@ skipping 14 matching lines @@
 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #
 # Copyright (c) 2009 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.
 
-# usage: rule_bison.py INPUT_FILE OUTPUT_DIR [BISON_EXE]
+# usage: rule_bison.py INPUT_FILE OUTPUT_DIR BISON_EXE [DEVELOPER_DIR]
 # INPUT_FILE is a path to either XPathGrammar.y.
 # OUTPUT_DIR is where the bison-generated .cpp and .h files should be placed.
 
 import errno
 import os
 import os.path
 import subprocess
 import sys
 
-assert len(sys.argv) == 3 or len(sys.argv) == 4
+assert len(sys.argv) == 4 or len(sys.argv) == 5
 
 inputFile = sys.argv[1]
 outputDir = sys.argv[2]
-bisonExe = 'bison'
-if len(sys.argv) > 3:
-    bisonExe = sys.argv[3]
+bisonExe = sys.argv[3]
+if len(sys.argv) > 4:
+    os.environ['DEVELOPER_DIR'] = sys.argv[4]
 
 pathToBison = os.path.split(bisonExe)[0]
 if pathToBison:
     # Make sure this path is in the path so that it can find its auxiliary
     # binaries (in particular, m4). To avoid other 'm4's being found, insert
     # at head, rather than tail.
     os.environ['PATH'] = pathToBison + os.pathsep + os.environ['PATH']
 
 inputName = os.path.basename(inputFile)
 assert inputName == 'XPathGrammar.y'
@@ skipping 41 matching lines @@
 
 # Rewrite the generated header with #include guards.
 outputH = os.path.join(outputDir, inputRoot + '.h')
 
 outputHFile = open(outputH, 'w')
 print >>outputHFile, '#ifndef %sH' % inputRoot
 print >>outputHFile, '#define %sH' % inputRoot
 print >>outputHFile, outputHContents
 print >>outputHFile, '#endif'
 outputHFile.close()