[CMake] How to determine origin of variable

[Martin Weber]

Hi all,

is there a way in CMake to detect, whether a variable has been set on 
the command-line (with the -D option) and not in a CMakelists.txt?

For example, GNU-make has the origin function do do something similar.

Thanks,
  Martin

-- 
☂ E-Mails sollten Text sein, Text und nur Text.
Wenn Gott gewollt hätte, dass E-Mails in HTML geschrieben würden,
endeten Gebete traditionell mit </amen>.