[subset] Work around OTS bug with FDSelect format 0

a049b98c88
https://github.com/khaledhosny/ots/pull/31

Fixes https://github.com/behdad/fonttools/issues/138

Lib/fontTools/subset.py

@@ -1372,7 +1372,14 @@ def subset_glyphs(self, s):
       del csi.file, csi.offsets
       if hasattr(font, "FDSelect"):
         sel = font.FDSelect
-        sel.format = None
+        # XXX We want to set sel.format to None, such that the most compact
+        # format is selected.  However, OTS was broken and couldn't parse
+        # a FDSelect format 0 that happened before CharStrings.  As such,
+        # always force format 3 until we fix cffLib to always generate
+        # FDSelect after CharStrings.
+        # https://github.com/khaledhosny/ots/pull/31
+        #sel.format = None
+        sel.format = 3
         sel.gidArray = [sel.gidArray[i] for i in indices]
       cs.charStrings = dict((g,indices.index(v))
                             for g,v in cs.charStrings.items()