fix support for non-GNU Linux systems (e.g. OS X)

[boegel]

(old internal ticket 16, 110)

We should try and support non-GNU Linux systems, for example OS X.

Known issues:

• no /proc/cpuinfo
• commands liketar have different options
• locale issues
  • when running EasyBuild in a session that orginates from on OS X system, you might run into problems like:

Catastrophic error: could not set locale "" to allow processing of multibyte characters

This can be fixed by setting the following environment variables on the OS X system:

export LANG=C; export LC_ALL=en_US

[boegel]

Currently, OpenMPI builds fails on OS X because of sanity check: shared libraries are not found (.dylib on OS X instead of .so).

[JensTimmerman]

OpenMPI already has dylib support in the sanity check, however, on OS X one lib does not seem to be build (f90.dylib ??)