Sorry, only a small point; probably you think of it yourself but
in the build instruction you write:
"Download the Allegro DLLs and *.lib files from my website:
http://www.lixgame.com/dow/alleg-5.2-dlls-libs.zip Extract this into your D installation's windows/ directory." (emphasis by me)
For that it is probably needed that the DLL-files are in a bin-folder and the .lib-files in a lib-folder or does it work out if you just spill the files in the windows subdirectory?
(You explain later though that DLL-files belong to bin and .lib-files to lib but that's connected to the backup strategy if you make own files, hm, and you mention at the beginning that these folders seem to be important.)