tm.texi (MD_UNWIND_SUPPORT): Document.

tm.texi (MD_UNWIND_SUPPORT): Document.

	* doc/tm.texi (MD_UNWIND_SUPPORT): Document.
	(MD_FALLBACK_FRAME_STATE_FOR): Update.
	* unwind-dw2.c (MD_UNWIND_SUPPORT): #include if defined.
	(uw_frame_state_for): Adjust MD_FALLBACK_FRAME_STATE_FOR invocation.
	(MD_FROB_UPDATE_CONTEXT): Remove default.
	(uw_update_context_1): Instead #ifdef invocation.
	* config/ia64/unwind-ia64.c (MD_UNWIND_SUPPORT): #include if defined.
	(uw_frame_state_for): Adjust MD_FALLBACK_FRAME_STATE_FOR invocation.
	* config/alpha/gnu.h (MD_FALLBACK_FRAME_STATE_FOR): Don't undef.
	(MD_UNWIND_SUPPORT): Undefine this instead.
	* config/i386/gnu.h: Likewise.
	* config/alpha/linux-unwind.h: New file, macro converted to
	function, extracted from..
	* config/alpha/linux.h (MD_FALLBACK_FRAME_STATE_FOR): ..this.
	(MD_UNWIND_SUPPORT): Define.
	* config/alpha/vms-unwind.h, config/alpha/vms.h: Likewise.
	* config/i386/linux-unwind.h, config/i386/linux.h,
	config/i386/linux64.h: Likewise.
	* config/ia64/linux-unwind.h, config/ia64/linux.h: Likewise.
	MD_HANDLE_UNWABI too.
	* config/mips/linux-unwind.h, config/mips/linux.h: Likewise.
	* config/pa/linux-unwind.h, config/pa/pa32-linux.h: Likewise.
	* config/rs6000/darwin-unwind.h, config/rs6000/darwin.h: Likewise.
	* config/s390/linux-unwind.h, config/s390/linux.h: Likewise.
	* config/sparc/linux-unwind.h, config/sparc/linux.h,
	config/sparc/linux64.h: Likewise.
	* config/sh/linux-unwind.h, config/sh/linux.h: Likewise, but merge
	SH_FALLBACK_FRAME_FLOAT_STATE into sh_fallback_frame_state.
	* config/rs6000/linux-unwind.h, config/rs6000/linux.h,
	config/rs6000/linux64.h: Likewise.  Split out get_sigcontext
	function.  Use ARG_POINTER_REGNUM for 32-bit temp reg too.

From-SVN: r87167