Address XXX comment in dis.py: inspect.py now attempts to reuse the dis.py compiler flag values before resorting to defining its own
diff --git a/Lib/inspect.py b/Lib/inspect.py
index 61c2502..f894da2 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -36,15 +36,25 @@
 import itertools
 import string
 import re
-import dis
 import imp
 import tokenize
 import linecache
 from operator import attrgetter
 from collections import namedtuple
-# These constants are from Include/code.h.
-CO_OPTIMIZED, CO_NEWLOCALS, CO_VARARGS, CO_VARKEYWORDS = 0x1, 0x2, 0x4, 0x8
-CO_NESTED, CO_GENERATOR, CO_NOFREE = 0x10, 0x20, 0x40
+
+# Create constants for the compiler flags in Include/code.h
+# We try to get them from dis to avoid duplication, but fall
+# back to hardcording so the dependency is optional
+try:
+    from dis import COMPILER_FLAG_NAMES as _flag_names
+except ImportError:
+    CO_OPTIMIZED, CO_NEWLOCALS = 0x1, 0x2
+    CO_VARARGS, CO_VARKEYWORDS = 0x4, 0x8
+    CO_NESTED, CO_GENERATOR, CO_NOFREE = 0x10, 0x20, 0x40
+else:
+    mod_dict = globals()
+    for k, v in _flag_names.items():
+        mod_dict["CO_" + v] = k
 
 # See Include/object.h
 TPFLAGS_IS_ABSTRACT = 1 << 20