[CMake] Is there a cookbook?

[Oliver Smith]

So it's late, and suddenly I find I can't remember how to configure 
cmake to compile any .xml file in a specific directory with an 
xml-to-header script we have. More importantly, I can't think of the 
right terms to find an answer, so I've spent a frustrating hour googling 
to no end.

Is there not a cmake cookbook or recipie book someplace? I really don't 
feel like figuring out, yet again, how to tell cmake "for every .xml 
file in ${folder} run ${command} to produce ${output}.h"... :)

- Oliver