[CMake] Redirect standard output to file

[Mathieu Malaterre]

'lo

  I am convinced this is an easy one, but I could not figure out how
to redirect standard output (from a process) into a file. Basically I
would need to run EXECUTE_PROCESS from within an ADD_CUSTOM_COMMAND
(run the process and capture output only when all the dependencies are
met).

-Thanks

-- 
Mathieu
Tel: +33 6 32 13 33 40