I've never tried to build Android libraries for A4.4 before, so I don't know how much help I'll be, but I'll try.
You can safely ignore the PNG not found, if you don't need it, otherwise you'll have to set the two variables (PNG_LIBRARY and PNG_INCLUDE_DIR) yourself, according to where they are located.
The next 3 errors all come from the addons. I'm not sure why they are there.
The last error has to do with not being able to find the RT_LIBRARY variable value. I'm not sure why that's there either. If you know what it is supposed to be, you can set that variable manually on your command line.
Elias is our resident expert on Android. Hopefully he knows what is going on.
Just a warning though, Allegro 4 is deprecated in favor of Allegro 5. So you might not get much help. If you can find out what's wrong and how to fix it, please submit a patch to the Allegro Development mailing list, or fork Allegro and fix it and make a pull request.