ceval, PyEval_MergeCompilerFlags: wasn't merging in the

CO_FUTURE_DIVISION flag.  Redid this to use Jeremy's PyCF_MASK #define
instead, so we dont have to remember to fiddle individual feature names
here again.

pythonrun.h:  Also #define a PyCF_MASK_OBSOLETE mask.  This isn't used
yet, but will be as part of the PEP 264 implementation (compile() mustn't
raise an error just because old code uses a flag name that's become
obsolete; a warning may be appropriate, but not an error; so compile() has
to know about obsolete flags too, but nobody is going to remember to
update compile() with individual obsolete flag names across releases either
-- i.e., this is the flip side of PyEval_MergeCompilerFlags's oversight).

Include/pythonrun.h

@@ -8,6 +8,8 @@ extern "C" {
 #endif
 
 #define PyCF_MASK (CO_GENERATOR_ALLOWED | CO_FUTURE_DIVISION)
+#define PyCF_MASK_OBSOLETE (CO_NESTED)
+
 typedef struct {
 	int cf_flags;  /* bitmask of CO_xxx flags relevant to future */
 } PyCompilerFlags;