re PR rtl-optimization/9812 ([m68k] ICE in extract_insn, at recog.c:2148)

PR optimization/9812
* rtl.h (mem_for_const_double): Delete prototype.
* varasm.c (mem_for_const_double): Delete function.
* config/m68k/hp320.h, config/m68k/linux.h, config/m68k/m68kelf.h,
config/m68k/m68kv4.h, config/m68k/netbsd-elf.h
(LEGITIMATE_PIC_OPERAND_P): Delete duplicate definitions.
* config/m68k/m68k.h (LEGITIMATE_CONSTANT_P): Disallow XFmode.
(LEGITIMATE_PIC_OPERAND_P): Delete CONST_DOUBLE tests.
* config/m68k/m68k.md (movxf): Add reload_in_progress guard.  Add
comment about confused support for XFmode constants.

From-SVN: r69027