How to run a command at compile time within Makefile generated by CMake?

Question

I would like to pass some options to a compiler. The option would have to be calculated at compile time - everytime when \'make\' is invoked, not when \'cmake\', so execute_

Answer 1

Does this work?

d=`perl -e"print qq(Whatever calculated at runtime);"`; g++ prog.cpp -o prog -DDATETIME=$$d