Added -pthreads option to C++ compiler
Added -pthreads option to C++ compiler

Should really be conditional per compiler, ofcourse (GCC specific flag).
This fixes the breakage from commit 1a6c4b3f45f7cd58da56

evdmade01/alpinocorpus,rug-compling/alpinocorpus,rug-compling/alpinocorpus,evdmade01/alpinocorpus,rug-compling/alpinocorpus