Enable the -Wstrict-prototypes warning for untrusted code in the Gyp build

build/build_nexe.py

 #!/usr/bin/python
 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """NEXE building script
 
 This module will take a set of source files, include paths, library paths, and
 additional arguments, and use them to build.
 """
@@ skipping 566 matching lines @@
               filename, outd))
         return True
     return False
 
   def Compile(self, src):
     """Compile the source with pre-determined options."""
 
     _, ext = os.path.splitext(src)
     if ext in ['.c', '.S']:
       bin_name = self.GetCCompiler()
-      extra = ['-std=gnu99']
+      extra = ['-std=gnu99', '-Wstrict-prototypes']
       if self.is_pnacl_toolchain and ext == '.S':
         extra.append('-arch')
         extra.append(self.arch)
     elif ext in ['.cc', '.cpp']:
       bin_name = self.GetCXXCompiler()
       extra = []
     else:
       if ext != '.h':
         self.Log('Skipping unknown type %s for %s.' % (ext, src))
       return None
@@ skipping 416 matching lines @@
       shutil.copy(objs[0], options.name)
     else:
       build.Generate(objs)
     return 0
   except Error as e:
     sys.stderr.write('%s\n' % e)
     return 1
 
 if __name__ == '__main__':
   sys.exit(Main(sys.argv))