Add support for Portals4 runtime.

CMakeLists.txt
	Set portals4/slurm include/lib paths.

include/clang/Config/config.h.cmake
	Add definition for Portals4 library path (cmake build).

include/clang/Config/config.h.in
	Add definition for Portals4 library path (configure/Makefile build).

lib/Driver/Tools.cpp
	Add compiler command line options for Portals4/Slurm includes and libraries.

runtime/libupc/CMakeLists.txt
	Add Portals4 cmake options and conditionals.
        Add rules to build p4 collectives.
        Parameterize build of clang-up-lib.h

runtime/libupc/config.h.cmake
	Add Portals4 cmake definitions.

runtime/libupc/portals4/gupcr_coll_init.upc
	Fix include as clang compiler wants to see the file quoted instead of bracketed.

runtime/libupc/portals4/gupcr_coll_reduce.in
	Ditto.

runtime/libupc/portals4/gupcr_coll_reduce.upc
	Rebuild.

runtime/libupc/portals4/gupcr_config.h
	Add necessary __USE_GNU if it is not already defined.

runtime/libupc/portals4/gupcr_gmem.c
	A warning fix.

runtime/libupc/portals4/gupcr_pts.h b/runtime/libupc/portals4/gupcr_pts.h
	Added Clang UPC definitions for pointer to shared types.

runtime/libupc/portals4/upc-lib.in
	Add defines for Spec 1.3 features.  Setup macros for pts definitions, properly arrange for inline headers,

runtime/libupc/portals4/gupcr_backtrace.c
runtime/libupc/portals4/gupcr_backtrace.h
runtime/libupc/portals4/gupcr_nb.upc
runtime/libupc/portals4/gupcr_nb_sup.c
runtime/libupc/portals4/gupcr_nb_sup.h
	New files.