gflags support

Put these defines earlier.
I don't like that Make doesn't warn on undefined variables

With the goal of making `assert obj.__dict__ is obj.__dict__` work.
I haven't seen people do that, but people (gflags, doctest? others?)
definitely need `assert globals() is globals()` to pass, which uses
the same mechanism.

The CMake build system doesn't have support for building the extension
modules, so use the self-hosting ability here.

Also, remove ext_pyston from run_deps since I think this would
become pretty anoying for debugging, where you can't run your test
if setup.py wouldn't run.  It's pretty rare that we actually use these
modules anyway.

add pkg-config to the install instructions

pyc number bump since we fixed the tuple parsing issue

Not sure if this is really a good feature for users, but taking
command line arguments from an environment variable is definitely
helpful for testing things like virtualenv which spawns a number (~10)
of subprocess.

Stats

Misc stuff for pycrypto

cuts down time to JIT 'pip' from 115ms to 65ms

this speeds up pip by several seconds because the pyston executable is very large.
CPython does not run into the problem because of the much smaller executable but has the same problem
when it has to retrieve the libc version of the pyston executable

support for 3arg pow, long("0xBB", 16) and long("0xBBL", 0)

bcrypt support

- Py_FatalError() has to be an expression (previously was multi-line macro)
- Add definitions of some PyObject_GC_* functions
- imp.load_dynamic

With these changes, bcrypt installs and runs

Amazingly, cffi compiled just fine with some missing function
declarations.  It provided implicit definitions for them and
then casted the "int" return type up to a PyObject*.

Some misc virtualenv + library support

(dependencies of bcrypt)
Increase test timeouts since this takes around 90s to install
in debug mode.

Base off of sys.prefix instead of sys.executable, since in
virtualenvs the executable is in an extra bin/ directory.

But not both cmp and key at the same time.
We might want to just switch to CPython's sort implementation for that.

Remove a workaround in req_install.py