--- xulrunner-18.0/mozilla/media/webrtc/trunk/tools/gyp/pylib/gyp/generator/mozmake.py.orig	2013-01-05 00:44:41.000000000 +0100
+++ xulrunner-18.0/mozilla/media/webrtc/trunk/tools/gyp/pylib/gyp/generator/mozmake.py	2013-01-13 20:13:40.033894757 +0100
@@ -114,6 +114,12 @@
   if dir and not os.path.exists(dir):
     os.makedirs(dir)
 
+def append_relative(base, rel):
+  if rel == '':
+    return base
+  else:
+    return base + '/' + rel
+
 def GetFlavor(params):
   """Returns |params.flavor| if it's set, the system's default flavor else."""
   flavors = {
@@ -142,9 +148,9 @@
 
 def WriteMakefile(filename, data, build_file, depth, topsrcdir, srcdir, relative_path, extra_data=None):
   if not os.path.isabs(topsrcdir):
-    topsrcdir = depth + "/" + topsrcdir
+    topsrcdir = append_relative(depth, topsrcdir)
   if not os.path.isabs(srcdir):
-    srcdir = depth + "/" + srcdir
+    srcdir = append_relative(depth, srcdir)
   #TODO: should compare with the existing file and not overwrite it if the
   # contents are the same!
   ensure_directory_exists(filename)
@@ -261,7 +267,7 @@
       qualified_target)
     build_file = os.path.abspath(build_file)
     rel_path, output_file = self.CalculateMakefilePath(build_file, target)
-    subdepth = self.depth + "/" + getdepth(rel_path)
+    subdepth = append_relative(self.depth, getdepth(rel_path))
     if self.WriteTargetMakefile(output_file, rel_path, qualified_target, spec, build_file, subdepth):
         # If WriteTargetMakefile returns True, then this is a useful target
       dirs.append(rel_path)
@@ -399,7 +405,7 @@
   # The relative path from objdir to gyp_file_dir
   srcdir = gyp.common.RelativePath(gyp_file_dir, objdir)
   # The absolute path to the source dir
-  abs_srcdir = topsrcdir + "/" + relative_srcdir
+  abs_srcdir = append_relative(topsrcdir, relative_srcdir)
   # The path to get up to the root of the objdir from the output dir.
   depth = getdepth(relative_srcdir)
   # The output directory.
@@ -408,9 +414,9 @@
   makefile_path = os.path.join(output_dir, "Makefile")
 
   def topsrcdir_path(path):
-    return "$(topsrcdir)/" + swapslashes(gyp.common.RelativePath(path, topsrcdir))
+    return append_relative("$(topsrcdir)", swapslashes(gyp.common.RelativePath(path, topsrcdir)))
   def objdir_path(path):
-    return "$(DEPTH)/" + swapslashes(gyp.common.RelativePath(path, objdir))
+    return append_relative("$(DEPTH)", swapslashes(gyp.common.RelativePath(path, objdir)))
 
   # Find the list of targets that derive from the gyp file(s) being built.
   needed_targets = set()