Add makefile rules for building test extensions via selfhost

ie running setup.py under Pyston.

Doesn't work yet, but (in a separate branch) was able to hack up
the distutils library until it did!
Import-related improvements

- Set the import "level" appropriately (takes absolute_import flag into account)
- Add a basic implementation of the __import__() function
- Fix a bug in existing import behavior (would not check sys.modules in certain
  cases)
stdlib improvements

- int(bool) works
- hash(bool) works
- str.find() now takes an optional "start" parameter
Convert Py_FatalError to a macro to get line numbers

Was tired of seeing bare "unimplemented" error messages and having
to track down where they were coming from -- especially tricky
when trying to add fork() support and the errors were in the child.
Add 's'/'z' case to do_mkvalue
Merge branch 'distutils'
[wip] remove _abcoll
[wip] don't know if this is right
[hack] hacks to get things working
[hax] disable more things
[hax] more hax
[hax] more hax
[real] Fix an import bug

For ensure_fromlist, were weren't first checking if the module
already existed in sys.modules, so we could potentially re-create it.
[hax?] formatting
[hax] more hax
[double check] some maybe real things?
[hax] ignore these errors
[maybe] some more makefile changes
[hax] and it works!
[hax] another stat