[CMake] cmake skips assembly files

[Kishore, Jonnalagadda (IE10)]

Assembly files explicitly given as source files for a target are
completely ignored. From google searches, it seems to be a known issue
and the solution lies with adding custom commands.

I am not familiar with adding custom commands. And thus have assembly
files assembled before building a target. Is there a wiki or a tutorial
on this?

Warm regards,
Kishore