The current patch allows the user to specify e.g.:

CFLAGS_NODIST="-march=core2" ./configure


So it would be surprising to get:

>>> import sysconfig
>>> sysconfig.get_config_var('CFLAGS_NODIST')
''


Now, we could restrict ourselves entirely to internal PY_CFLAGS_NODIST,
but I think exposing the feature is really useful if users or
distributors want to specify optimizations, FPU behavior or other
things that should not generally show up in distutils.