Trng with openMP on OSX

To make trng compile on Mac OSX ML with OpenMP I had to make a few changes. 
The main change is in acinclude.m4 and based on http://savannah.gnu.org/patch/?7893
which is a patch fix compilation of OpenMP on OS X which presently fail due to compiler error in the code detecting openmp flags. This is a known difference in the way gcc-llvm behave and fixed in the patch linked above. 

Furthermore I changed the permission of the configure and install scripts to allow execution of them.

I submit this here in the hope that it is useful for others.