libgomp/

	libgomp/
	* target.c (gomp_offload_image_to_device): Rename to ...
	(gomp_load_image_to_device): ... here.
	(GOMP_offload_register): Adjust call.
	(gomp_init_device): Likewise.
	(gomp_unload_image_from_device): New.  Broken out of ...
	(GOMP_offload_unregister): ... here.  Call it.
	(gomp_unload_device): New.
	* libgomp.h (gomp_unload_device): Declare.
	* oacc-init.c (acc_shutdown_1): Unload from device before deleting
	mem maps.

	gcc/
	* config/nvptx/mkoffload.c (process): Add static destructor call.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@226039 138bc75d-0d04-0410-961f-82ee72b054a4