Harry Henry Gebel: get extra compiler flags from the CFLAGS environment variable.
Harry Henry Gebel: get extra compiler flags from the CFLAGS environment
variable.

(Is this really needed?  Can we drop it when the config file mechanism
allows users to set compiler flags in setup.cfg?)

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator