[CMake] Total cmake newbie needs some help

[Edgar]

I've already looked at the cmake tutorial, and it isn't that great. It 
starts really simple but then goes into really complex things that most 
people might not even use.

Also, there is currently no such thing as 'The Openlayer community' - 
the project is unsupported, and no longer in active development due to 
inactive development for Allegro 4. So if there is anyone who can help 
it is this cmake mailing list, and that's all.

I am trying to get Openlayer 2pt1 to build with MinGW 4.5 and up, which 
it currently doesn't do. I've been able to fix compilation errors, but 
not build errors related to cmake.

I have these problems -
1) Cmake cannot find ZLIB
2) Cmake cannot find LIBPNG
3) There are undefined reference errors during the linking process for 
the OpenLayer demos, and I don't know how to properly link the necessary 
libraries using cmake.

There are some .cmake files named FindALLEGRO, and FindFREETYPE, and 
those work properly. Do I need to create similar cmake files for zlib 
and libpng?

How does cmake find required libraries and link to them?