Reapplied changeset 31ff9550fba6 (bug 870073)

config/tests/unit-writemozinfo.py

@@ -175,12 +175,16 @@ class TestWriteJson(unittest.TestCase):
         """
         write_json(self.f, env={'OS_TARGET':'WINNT',
                                 'TARGET_CPU':'i386',
+                                'TOPSRCDIR':'/tmp',
+                                'MOZCONFIG':'foo',
                                 'MOZ_WIDGET_TOOLKIT':'windows'})
         with open(self.f) as f:
             d = json.load(f)
             self.assertEqual('win', d['os'])
             self.assertEqual('x86', d['processor'])
             self.assertEqual('windows', d['toolkit'])
+            self.assertEqual('/tmp', d['topsrcdir'])
+            self.assertEqual(os.path.normpath('/tmp/foo'), d['mozconfig'])
             self.assertEqual(32, d['bits'])
 
     def testFileObj(self):

config/writemozinfo.py

@@ -30,7 +30,10 @@ def build_dict(env=os.environ):
                         ', '.join(missing))
 
     if 'MOZCONFIG' in env:
-        d["mozconfig"] = env["MOZCONFIG"]
+        mozconfig = env["MOZCONFIG"]
+        if 'TOPSRCDIR' in env:
+            mozconfig = os.path.join(env["TOPSRCDIR"], mozconfig)
+        d['mozconfig'] = os.path.normpath(mozconfig)
 
     if 'TOPSRCDIR' in env:
         d["topsrcdir"] = env["TOPSRCDIR"]