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.)