ninja windows: support precompiled headers

pylib/gyp/xcode_emulation.py

Index: pylib/gyp/xcode_emulation.py
diff --git a/pylib/gyp/xcode_emulation.py b/pylib/gyp/xcode_emulation.py
index 9ed98d5fab53fc44def0cb0474057bdd948ec9a1..66dab8cd9caed9babe9193f89dc35d2309db8b38 100644
--- a/pylib/gyp/xcode_emulation.py
+++ b/pylib/gyp/xcode_emulation.py
@@ -732,10 +732,9 @@ class MacPrefixHeader(object):
     return self.compiled_headers[lang] + '.gch'
 
   def GetObjDependencies(self, sources, objs):
-    """Given a list of source files and the corresponding object files, returns
-    a list of (source, object, gch) tuples, where |gch| is the build-directory
-    relative path to the gch file each object file depends on.  |compilable[i]|
-    has to be the source file belonging to |objs[i]|."""
+    """Given a list of source files and the corresponding object files,
+    returns a list of gch files, where |gch| is the build-directory relative

[Nico, 2012/05/23 20:53:29]

My guess is that this interface change will break preprocessed headers in the
mac/make build.

[scottmg, 2012/05/24 20:34:39]

Thanks, those "unused" returns make a lot more sense now! Ahem.

+    path to the gch file each object file depends on."""
     if not self.header or not self.compile_headers:
       return []
 
@@ -749,20 +748,20 @@ class MacPrefixHeader(object):
         '.mm': 'mm',
       }.get(ext, None)
       if lang:
-        result.append((source, obj, self._Gch(lang)))
+        result.append(self._Gch(lang))
     return result
 
-  def GetGchBuildCommands(self):
-    """Returns [(path_to_gch, language_flag, language, header)].
+  def GetPchBuildCommands(self):
+    """Returns [(path_to_gch, language_flag, language, header, extra_vars)].
     |path_to_gch| and |header| are relative to the build directory.
     """
     if not self.header or not self.compile_headers:
       return []
     return [
-      (self._Gch('c'), '-x c-header', 'c', self.header),
-      (self._Gch('cc'), '-x c++-header', 'cc', self.header),
-      (self._Gch('m'), '-x objective-c-header', 'm', self.header),
-      (self._Gch('mm'), '-x objective-c++-header', 'mm', self.header),
+      (self._Gch('c'), '-x c-header', 'c', self.header, []),
+      (self._Gch('cc'), '-x c++-header', 'cc', self.header, []),
+      (self._Gch('m'), '-x objective-c-header', 'm', self.header, []),
+      (self._Gch('mm'), '-x objective-c++-header', 'mm', self.header, []),
     ]