* coffread.c (coff_symtab_read) [SEM]: Remove code, macro can

	* coffread.c (coff_symtab_read) [SEM]: Remove code, macro can
	never be defined.
	* dbxread.c (process_one_symbol) [BLOCK_ADDRESS_ABSOLUTE]:
	Remove, no longer needed.
	* hppa-tdep.c (N_SET_MAGIC): Remove, no longer used.
	* config/pa/xm-hppab.h (SEEK_SET, SEEK_CUR, SEEK_END): Ditto.
	* config/mips/tm-mipsm3.h (NUMERIC_REG_NAMES): Ditto.
	* config/mips/mipsm3.mt (TDEPFILES): Remove mipsread.o.
Cruft discovered while working on GDB internals manual