Portals4 runtime builds without errors.

runtime/libupc/portals4
	gupcr_backtrace.c
	gupcr_backtrace.h
	gupcr_nb.upc
	gupcr_nb_sup.c
	gupcr_nb_sup.h
	- Added non-blacking and backtrace support

	gupcr_coll_init.upc
	gupcr_coll_reduce.in
	gupcr_coll_reduce.upc
	gupcr_config.h
	gupcr_gmem.c
	gupcr_pts.h
	upc-lib.in
	- Various fixes to compile with clang

runtime/libupc
	CMakeLists.txt
	config.h.cmake
	- Added missing configuration variables
	- Added build of reduce collective tests