To compile Nethack for the allegro interface:

             First, follow the instructions in the sys\msdos directory 
        to compile a non-allegro binary and all the game datafiles.

             Then, rename "makefile.alg" to "makefile" and run make.

             The Allegro makefile DOES NOT automatically create the 
        neccesary tile files.  To create them manually, run 
        "tile2bmp.exe" in the src\ directory, tile2bmp is created 
        automatically by make.  Then create an index for these tiles 
        with "tileidx > index", "move index ..\tiles".

             Alternately, if your version of nethack has all the same 
        monsters/objects/traps/terrain types as 3.3.0, you can just 
        download a tileset. (currently only available with the 
        binaries.)