Was giving a gcc error for a local named "zero"

--HG--
rename : tests/compile/bad_c_struct_T252.pyx => tests/run/bad_c_struct_T252.pyx

--HG--
rename : tests/compile/coercearraytoptr.pyx => tests/run/coercearraytoptr.pyx

Bug and fix reported by Mark Lodato.

Incorporate the changes of cython_freeze:
* fix when compiling on Python 3 (Issue #434)
* fix floating point issues on FreeBSD

To get the output of cython_freeze to compile with both Python 2 and
Python 3, I copied the contents of Python-3.1.1/Modules/python.c, with
some slight modifications.  The main issue is that Python 3 uses
wchar_t, while Python 2 uses char.  It also appears that the
Py_FlushLine/PyErr_Clear is not needed in Python 3.

Related to #434: "main() function generated by --embed doesn't compile
in Py3"

The cython_freeze-generated executable exits with code 1 if something
wrong happens, unless a SystemExit exception occurred, in which case it
returns the value passed to sys.exit().  In order to differentiate
between the two cases, change the two example Cython modules to exit(2).

Copy the fix for floating point exceptions on FreeBSD from Python's
Module/python.c.

Python 2 cannot compile with strict aliasing, so the Cython modules
should really be compiled with -fno-strict-aliasing.  See Issue #395.

Add a target (with alias "html") to build README.html from README.txt
using rst2html.  This is not run by default.