* gdb.info*: added to distribution. These are ordinary info

	* gdb.info*: added to distribution.  These are ordinary info
	files, formatted from gdb.texinfo (via gdb-all.texinfo, see
	Makefile)---but due to use of texinfo 2, can't count on makeinfo
	to generate these, so we distribute them already formatted.

	* gdb.texinfo: included full Info node and menu crud (as generated
	by C-u M-x texinfo-master-menu using the texinfo-2 elisp code).

	* Makefile: updated "gdb.dvi" target to use M4 preprocessor;
	put in comments-for-future gdb.info target (one day makeinfo will
	work again).