* desc-cpu.scm (cgen-desc.h): Don't print virtual enums.

	* desc-cpu.scm (cgen-desc.h): Don't print virtual enums.
	* sid-cpu.scm (cgen-desc.h): Ditto.
	* enum.scm (enum-builtin!): New function.
	* read.scm (reader-install-builtin!): Call it.
	* rtl-c.scm (s-convop): Delete, replaced with ...
	(s-int-convop, s-float-convop): ... new fns.
	(ext, zext, trunc): Update.
	(fext, ftrunc, float, ufloat, fix, ufix): Update.
	* rtx-funcs.scm (fext, ftrunc, float, ufloat, fix, ufix): New parameter
	`how'.
	* cpu/mep-fmax.cpu (fcvtsw): Update.
	* cpu/sh.cpu (h-fsd, h-fmov): Update.
	* doc/rtl.texi (float-convop): Update.

	* frv.cpu (floating-point-conversion): Update call to fp conv op.
	(floating-point-dual-conversion, ne-floating-point-dual-conversion,
	conditional-floating-point-conversion, ne-floating-point-conversion,
	float-parallel-mul-add-double-semantics): Ditto.