Result = AddPackFile(#Pack, Filename$, PackedFilename$)Description
Add and compress the file to the specified pack previously created with CreatePack(). Adding a large file can take a long time.
#Pack The pack to use. Filename$ The filename$ to add to the pack. PackedFilename$ The filename to use in the archive to store the file.
Nonzero if the file has been successfully added to the packfile. If the file can't be compressed, it will be stored as is in the packfile.