python: Fix various contamination issues leading to broken/missing c modules

python: Fix various contamination issues leading to broken/missing c modules

The move of libcrypto to /lib instead of /usr/lib has broken the _hashlib module
compilation. There were also a number of other failing modules which should
have been building correctly. This turned out partly to be the /lib issue
but also due to a number of native paths creeping into compiler commandlines.

These changes add in /lib as part of the searh directory and remove
a number of host contamination issues within setup.py. Post release we
should really further go through this file and just delete large sections
of it as its hard to be sure what strange paths python is injecting as
search paths.

This patch also fixes issues where re-execution of the compile task
would corrupt the Makefile in various ways, again leading to puzzling
paths within the configuration.

(From OE-Core rev: 20e2761e1da1cb5dcd267e161f2a6b6a429e9f39)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>