as data0_frchainP
* write.c (write_object_file): various changes to handle data in
the BSS segment in much the same was as stuff in the DATA segment.
* subsegs.c (subseg_change): allow and handle a change into SEG_BSS.
* expr.c(expr): allow SEG_REGISTER in expressions.
* read.c(pseudo_set): register expressions can be the source of a
set.
* subsegs.c (subseg_new): Now -R forces all changes to SEG_DATA to
goto SEG_TEXT (if a.out)
* write.c (write_object_file): If a.out don't use the old way for
-R.
* config/obj-a.out (s_sect): complain if the user tries to use a
subsegment with a value which might interfere with out -R hackery.
* config/tc-m68k.c (m68k_reg_parse): lookup names in symbol table
rather than use ugly if tree. (init_regtable): insert register
names into symbol table.
