as_bad_subtract

as_bad_subtract

Many places report errors of the nature "can't resolve a - b".
This provides a utility function to report such errors consistently.
I removed the section reporting and quotes around symbol names while I
was at it.  Compare
ifunc-2.s:4: Error: can't resolve `bar1' {.text.1 section} - `foo1' {.text.1 section}
with
ifunc-2.s:4: Error: can't resolve bar1 - foo1

In many cases the section names don't help the user very much in
figuring out what went wrong, and the quotes if present arguably ought
to be placed around the entire expression:
can't resolve `bar1 - foo1'

The patch also tidies some tc_get_reloc functions that leak memory on
error paths.

	* write.h (as_bad_subtract): Declare.
	* write.c (as_bad_subtract): New function.
	(fixup_segment): Use as_bad_subtract.
	* config/tc-arc.c (md_apply_fix): Likewise.
	* config/tc-avr.c (md_apply_fix, tc_gen_reloc): Likewise.
	* config/tc-cris.c (md_apply_fix): Likewise.
	* config/tc-d10v.c (md_apply_fix): Likewise.
	* config/tc-d30v.c (md_apply_fix): Likewise.
	* config/tc-ft32.c (md_apply_fix): Likewise.
	* config/tc-h8300.c (tc_gen_reloc): Likewise.
	* config/tc-m68hc11.c (md_apply_fix): Likewise.
	* config/tc-mmix.c (mmix_frob_file): Likewise.
	* config/tc-mn10200.c (tc_gen_reloc): Likewise.
	* config/tc-nds32.c (nds32_apply_fix): Likewise.
	* config/tc-pru.c (md_apply_fix): Likewise.
	* config/tc-riscv.c (md_apply_fix): Likewise.
	* config/tc-s12z.c (md_apply_fix): Likewise.
	* config/tc-s390.c (md_apply_fix): Likewise.
	* config/tc-tilegx.c (md_apply_fix): Likewise.
	* config/tc-tilepro.c (md_apply_fix): Likewise.
	* config/tc-v850.c (md_apply_fix): Likewise.
	* config/tc-vax.c (md_apply_fix): Likewise.
	* config/tc-xc16x.c (tc_gen_reloc): Likewise.
	* config/tc-xgate.c (md_apply_fix): Likewise.
	* config/tc-xstormy16.c (xstormy16_md_apply_fix): Likewise.
	* config/tc-xtensa.c (md_apply_fix): Likewise.
	* config/tc-z80.c (tc_gen_reloc): Likewise.
	* config/tc-spu.c (md_apply_fix): Likewise.
	(tc_gen_reloc): Delete dead code.  Free memory on error.
	* config/tc-cr16.c (tc_gen_reloc): Use as_bad_subtract.  Free
	on error.
	* config/tc-crx.c (tc_gen_reloc): Likewise.
	* config/tc-ppc.c (tc_gen_reloc): Likewise.
	* testsuite/gas/i386/ifunc-2.l: Adjust to suit changed error message.
	* testsuite/gas/mips/lui-2.l: Likewise.
	* testsuite/gas/tic6x/reloc-bad-1.l: Likewise.