* Makefile.in (MACHMODE_H): Add @extra_modes_file@.
	* configure.in: If $srcdir/config/${cpu_type}/${cpu_type}-modes.def
	exists, substitute its pathname as @extra_modes_file@, define
	EXTRA_MODES_FILE to be an appropriate string to #include it
	with, and define EXTRA_CC_MODES to 1.

	* machmode.def: Update comments.  Include EXTRA_MODES_FILE if
	it's defined.  Get rid of redundancy in calling sequence for
	CC; don't use it to define CCmode, to avoid a warning.
	* libgcc2.c: Include symcat.h for the sake of machmode.def.

	* arc-modes.def, arm-modes.def, c4x-modes.def, i386-modes.def,
	i960-modes.def, ia64-modes.def, m88k-modes.def, mmix-modes.def,
	pa-modes.def, pdp11-modes.def, rs6000-modes.def, sparc-modes.def:
	New files.
	* arc.h, arm.h, c4x.h, i386.h, i960.h, ia64.h, m88k.h, mmix.h,
	pa.h, pdp11.h, rs6000.h, sparc.h: Don't define EXTRA_CC_MODES.

	* doc/sourcebuild.texi, doc/tm.texi: Document new scheme for
	defining extra CC modes.

From-SVN: r54478