Current bytecode optimizer works only when all arguments are
constants.

With the attached small patch, adjacent successive literal arguments
of `concat' will become optimized to a string respectively.

	Make successive literals of `concat' optimized to a string.
	* byte-opt.el (byte-optimize-form-code-walker): call
	byte-optimize-concat-args for `concat'.
	(byte-optimize-concat-args): New function.

Regards,
Shigeru