Pull up following revision(s) (requested by martin in ticket #1006):
external/gpl3/gcc/dist/gcc/config/sparc/constraints.md: revision 1.2
external/gpl3/gcc/dist/gcc/config/sparc/predicates.md: revision 1.2
external/gpl3/gcc/dist/gcc/config/sparc/sync.md: revision 1.2
Port from newer gcc:
Add a "mem_noofs_operand" predicate and corresponding "w" constraint.
Use those instead of "memory_reg_operand"/"m" for some atomic instrinsic
patterns: casx (and friends) do not accept an offset from the pointer
register (they are synthetic instructions mapping to e.g. casxa [..]
ASI_P, ... and the opcode space encoding offsets in other instructions
is needed to encode the ASI here).
This fixes the build of gtk+-3.10.6 from pkgsrc on sparc64.

(bouyer)