* libgcc2.c: Change all conditionals testing
	LIBGCC2_LONG_DOUBLE_TYPE_SIZE == 96 to == 80.
	* libgcc2.h: Likewise.
	* config/i386/i386.c (ix86_init_mmx_sse_builtins): Set
	TYPE_PRECISION of float80_type to 80.
	* config/ia64/ia64.c (ia64_init_builtins): Set TYPE_PRECISION
	of fpreg_type and float80_type to 80.
	* config/i386/i386.h, config/ia64/ia64.h, config/m68k/m68k.h
	* config/m68k/netbsd-elf.h:
	Change LONG_DOUBLE_TYPE_SIZE and possibly LIBGCC2_LONG_DOUBLE_TYPE_SIZE
	to evaluate to 80 whenever they would formerly have evaluated to 96.
	* config/i386/sco5.h: Remove unnecessary redefinition of
	LONG_DOUBLE_TYPE_SIZE.
	* doc/rtl.texi: Clarify uses of XFmode and TFmode.
	* config/i386/i386-modes.def: Use FRACTIONAL_FLOAT_MODE for
	XFmode, with a bitsize of 80.  Update commentary.
	* config/ia64/ia64-modes.def: Likewise.
	* config/m68k/m68k-modes.def: Likewise.

From-SVN: r85232