* opt-read.awk: New.  Split out of optc-gen.awk and opth-gen.awk.
	* optc-gen.awk: Move common code to opt-read.awk.
	* opth-gen.awk: Likewise.
	* Makefile.in (options.c, s-options-h): Update to use
	opt-read.awk.

From-SVN: r173995