[CMake] FW: Generating warnings for undefined variables?

[Trevor Kellaway]

Alex,
 
> I think not having to declare variables is as it is in most scripting 
> languages (which doesn't automatically mean it's the best 
> way, but at least 
> cmake is not different here).

It would be nice to have an option (like VB's "strict") to turn on this
checking, having recently been bitten by this issue, in my case someone
had got an add dependency variable case wrong, which took some time to
chase down.

I was also surprised that ADD_CUSTOM_COMMAND's DEPEND will happily take
an undefined variable without complaint, iow a null arg to DEPEND (CMake
2.4)

-Trevor