Add 64-bit support for RTEMS using the ELFv2 ABI with 64-bit long
double.

gcc/
	* config.gcc (powerpc-*-rtems*): Remove rs6000/eabi.h.  Add
	rs6000/biarch64.h.
	* config/rs6000/rtems.h (ASM_DECLARE_FUNCTION_SIZE): New macro.
	(ASM_OUTPUT_SPECIAL_POOL_ENTRY_P): Likewise.
	(CRT_CALL_STATIC_FUNCTION): Likewise.
	(ASM_DEFAULT_SPEC): New define.
	(ASM_SPEC32): Likewise.
	(ASM_SPEC64): Likewise.
	(ASM_SPEC_COMMON): Likewise.
	(ASM_SPEC): Likewise.
	(INVALID_64BIT): Likewise.
	(LINK_OS_DEFAULT_SPEC): Likewise.
	(LINK_OS_SPEC32): Likewise.
	(LINK_OS_SPEC64): Likewise.
	(POWERPC_LINUX): Likewise.
	(PTRDIFF_TYPE): Likewise.
	(RESTORE_FP_PREFIX): Likewise.
	(RESTORE_FP_SUFFIX): Likewise.
	(SAVE_FP_PREFIX): Likewise.
	(SAVE_FP_SUFFIX): Likewise.
	(SIZE_TYPE): Likewise.
	(SUBSUBTARGET_OVERRIDE_OPTIONS): Likewise.
	(TARGET_64BIT): Likewise.
	(TARGET_64BIT): Likewise.
	(TARGET_AIX): Likewise.
	(WCHAR_TYPE_SIZE): Likewise.
	(WCHAR_TYPE): Undefine.
	(TARGET_OS_CPP_BUILTINS): Add 64-bit PowerPC defines.
	(CPP_OS_DEFAULT_SPEC): Use previous CPP_OS_RTEMS_SPEC.
	(CPP_OS_RTEMS_SPEC): Delete.
	(SUBSUBTARGET_EXTRA_SPECS): Remove cpp_os_rtems.  Add
	asm_spec_common, asm_spec32, asm_spec64, link_os_spec32, and
	link_os_spec64.
	* config/rs6000/t-rtems: Add mcpu=e6500/m64 multilibs.

libgcc/
	* config/rs6000/ibm-ldouble.c: Disable if defined __rtems__.

From-SVN: r250652