mangle file mode to avoid breaking rebuilds

Change-Id: Id436bdbf3a307a3a3c9735ad911e397a21ab701b

nss/nsinstall.py

@@ -87,6 +87,10 @@ def nsinstall(argv):
     # mode is specified
     try:
       options.m = int(options.m, 8)
+      # I have no idea why nss insists on using this mode for installed headers.
+      # It causes problems with updating the files during a rebuild.
+      if options.m == 0444:
+        options.m = 0644
     except:
       sys.stderr.write('nsinstall: ' + options.m + ' is not a valid mode\n')
       return 1