common-target-def.h, [...]: New files.

common-target-def.h, [...]: New files.

	* common/common-target-def.h, common/common-target.def,
	common/common-target.h, common/config/default-common.c,
	common/config/pa/pa-common.c: New files.
	* Makefile.in (common_out_file, common_out_object_file,
	COMMON_TARGET_H, COMMON_TARGET_DEF_H): New.
	(OBJS-libcommon-target): Include $(common_out_object_file).
	(prefix.o): Update dependencies.
	($(common_out_object_file), common/common-target-hooks-def.h,
	s-common-target-hooks-def-h): New.
	(s-tm-texi): Also check timestamp on common-target.def.
	(build/genhooks.o): Update dependencies.
	* config.gcc (common_out_file, target_has_targetm_common): Define.
	* config/pa/som.h (ALWAYS_STRIP_DOTDOT): Replace with
	TARGET_ALWAYS_STRIP_DOTDOT.
	* configure.ac (common_out_object_file): Define.
	(common_out_file, common_out_object_file): Substitute.
	(common): Create directory.
	* configure: Regenerate.
	* doc/tm.texi.in (targetm_common): Document.
	(TARGET_ALWAYS_STRIP_DOTDOT): Add @hook entry.
	* doc/tm.texi: Regenerate.
	* genhooks.c (hook_array): Also include common/common-target.def.
	* prefix.c (tm.h): Don't include.
	(common/common-target.h): Include.
	(ALWAYS_STRIP_DOTDOT): Don't define.
	(update_path): Use targetm_common.always_strip_dotdot instead of
	ALWAYS_STRIP_DOTDOT.
	* system.h (ALWAYS_STRIP_DOTDOT): Poison.

From-SVN: r175052