policy: remove unused policynoc and policynocffi constants

cffi: remove superfluous "if True" blocks

cffi: split modules from pure The copyright lines are updated per change history. cffi/osutil.py isn't tested since I have no access to OS X machine right now, sorry.

policy: extend API version checks for cffi This is just a stub for future extension. I could add a version constant to CFFI modules by putting it to both ffi.set_source() and ffi.cdef(), but that doesn't seem right. So for now, cffi modules will be explicitly unversioned (i.e. version constant must be undefined or set to None.) We can revisit it later when we need to consider CFFI support more seriously.

filterpyflakes: allow reexporting pure symbols from cffi modules cffi modules will do 'from ..pure.<module> import *'.

import-checker: guess names of C extension modules Since extension modules aren't included in the list of source files, they need to be populated somehow. Otherwise the import from cext/cffi would be treated as a global one.

import-checker: convert localmods to a set of module names This makes it easy to add a source-less module name to the set.

import-checker: allow importing symbols from pure modules This allows us to re-export pure functions from cffi modules: # mercurial/cffi/base85.py from ..pure.base85 import *

cffi: put compiled modules into mercurial.cffi package Don't pollute the top-level namespace.

cffi: rename build scripts This frees up cffi package for modules to be split from pure.