Fix# 20043 & 20392
The issue is that OSX lib does not implement TLS (Thread Local Storage), so libgomp uses pthread functions to read/write thread specific vars.
But this implementation is currently (gcc 4.2) buggy : the write function is called only at lib start (in main thread), and the var is undefined for background thread.
The workaround is to perform this gomp_tls_key var write at beginning of background threads that use openMP. (Currently: render & fluidsim)
interface for it is still missing. Right now there is only a simple hard coded
example, that moves a single control particle with strong attraction
and velocity forces through the domain.
I added more detailed information about the control code to the wiki
http://wiki.blender.org/index.php/SoCFluidDevelDoc#The_Fluid-Control_Branch ,
together with some thoughts on how a Blender integration could be done.
