[CMake] EXEC_PROGRAM and inheritance

[Brian Hone]

Hi folks,

I see a lot of posts which seem to indicate that there is popular 
support for allowing inheritance of the EXEC_PROGRAM command to 
subdirectories.

Looking at the code, commands which allow inheritance simply add the 
following to the .h file:

virtual bool IsInherited <cid:part1.07070002.03030705 at baesystems.com>() {return true;}


Am I missing something?  Would this cause the command to be re-executed 
from sub-directories, or the value to be cached and saved?  It's a real 
devil to save the value from an external command and pass it around, 
which sort of defeats the purpose of an external command.

Brian