Minor: Bugfix: Including unistd.h for [R|W]_OK.
Initial commit for MACVEC module.
Converted MACVEC module to 100% C.

This patch discards the std::set, std::map and std::stack types to use
perfexpert_list_t type and arrays. The array is statically declared and hence
limited in size (and also wasteful) so a better implementation is needed in the
future.