uClibc compatibility for core

[kunkku]

Make the core compile with uClibc (and more compliant with POSIX)

[prymitive]

This broke uWSGI on (at least) ubuntu:

cc1: warnings being treated as errors
core/utils.c: In function ‘uwsgi_set_cpu_affinity’:
core/utils.c:4659: error: implicit declaration of function ‘CPU_ZERO’
core/utils.c:4664: error: implicit declaration of function ‘CPU_SET’
core/utils.c:4675: error: implicit declaration of function ‘sched_setaffinity’
make: *** [all] Błąd 1

@unbit Maybe it's time to hook up travis-ci.org? Beside broken python2.5 plugin on gcc everything works fine with the config I made.

travis build

[unbit]

reverted, need some #ifdef

[unbit]

i think the problem is in sched.h include, i will look at it later