Thanks Edgar, From what I read CMake and QT are Windows based. Am I misunderstanding? Also I found a version of allegro with the needed liballeg_s file on my jump drive. Is this a common file for both Windows and Linux, or is it unique to Linux. I may not have to worry about recompiling as I may have my original copy I compiled before.
CMake is cross platform. Install it with apt or zypper or whatever Slackware uses for a package manager, command line or GUI based or whatever.
As an alternative to cmake-gui, you can use ccmake, but I hate TUIs so I will never use it. cmake-gui is just easier, but you may have to install GTK along with it.
liballeg_s.a is a static version of Allegro, yes, but if you build allegro yourself, it will be called liballeg.a .
You can't use the same lib for Windows and Linux. They are incompatible, even if you build it with gcc.
Allegro 4.4 uses allegro-config. I've never used it before, so I don't know how it works, but I think it's pretty similar to pkg-config. If you call it without arguments, it should output help text.