Unused but documented target macros

[mike stump]

> Date: Mon, 7 Jan 2002 23:07:00 +0000 (GMT)
> From: "Joseph S. Myers" <jsm28@cam.ac.uk>
> To: <gcc@gcc.gnu.org>

> The following target macros are documented in tm.texi, and mostly have
> some definitions or at least commented out definitions in target headers,
> but don't seem to be used anywhere in GCC.  ADA_LONG_TYPE_SIZE is new;  
> presumably the code to use it will be committed in future?  Should the
> others be removed from GCC, or are any of them in a similar situation
> (code to use them not yet committed)?

> ASM_OUTPUT_EH_REGION_BEG
> ASM_OUTPUT_EH_REGION_END
> DOESNT_NEED_UNWINDER
> EH_TABLE_LOOKUP
> OMIT_EH_TABLE

These I think are ejecta matter.  I think they can be removed.