OpenMP crashes in debug mode
Curretly OpenMP only works in release mode, in debug mode there are some allocations being made, and with the current GC design allocating from OMP threads is not supported. Some seqs (for example calling is_C_Contiguous does allocate a seq) and strings are being allocated in the OMP threads, why? 

Investigate further, do we need to mark OMP functions as Gcsafe or something?