[PATCH 4/7] OpenMP 4.0 offloading infrastructure: lto-wrapper.

[PATCH 4/7] OpenMP 4.0 offloading infrastructure: lto-wrapper.

gcc/
	* gcc.c (spec_host_machine, accel_dir_suffix): New variables.
	(process_command): Tweak path construction for the possibility
	of being configured as an offload compiler.
	(driver::maybe_putenv_OFFLOAD_TARGETS): New function.
	(driver::main): Call maybe_putenv_OFFLOAD_TARGETS.
	(driver::set_up_specs): Tweak path construction for the possibility of
	being configured as an offload compiler.
	* lto-wrapper.c (OFFLOAD_TARGET_NAMES_ENV): Define.
	(offload_names, offloadbegin, offloadend): New static variables.
	(free_array_of_ptrs, parse_env_var, access_check, compile_offload_image)
	(compile_images_for_offload_targets, copy_file, find_offloadbeginend):
	New static functions.
	(run_gcc): Determine whether offload sections are present.  If so, run
	compile_images_for_offload_targets and return the names of new generated
	objects to linker.  If there are offload sections, but no LTO sections,
	then return the copies of input objects without link-time recompilation.

lto-plugin/
	* lto-plugin.c (OFFLOAD_SECTION, OFFLOAD_SECTION_LEN): Define.
	(struct plugin_objfile): Add new field "offload".
	(process_offload_section): New static function.
	(claim_file_handler): Claim file if it contains offload sections.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@217491 138bc75d-0d04-0410-961f-82ee72b054a4