Fix timming issue with macOS

Some old versions of OS X, previous to Sierra, do not support
CLOCK_MONOTONIC based timer, added support for MATCH timer.

Support {Net,Open}BSD OSS

Fixed this build failure building raylib:
http://www.cpantesters.org/cpan/report/a069fade-0e1f-11e8-a1cf-bb670eaac09d

Functionality is untested, but it now compiles on NetBSD. A quick google search for
libossaudio OpenBSD indicates that linking to libossaudio would be required there too.

raylib issue: raysan5/raylib#463

Fixes issue #7

This issue affects the OpenSL and SDL backends.

This commit implements a generic method for determining the name which
simply performs an enumeration and compares against IDs. The problem
with this technique is that it cannot know the name of the default
device without help from the backend.