[CMake] How do I generate a preprocessed file?

[Piotr Wyderski]

Tyler Roscoe wrote:

> I don't know of a single place to gather all the flags CMake will pass
> to your compiler.

I've chceked those variables, but they provide not
a very useful part of the command line, for example
CMAKE_CXX_FLAGS_RELEASE gives me only
-O3 -DNDEBUG.

> get_target_properties() might also be of use.

It is a very promising direction indeed, however
after some hacking all I have from GET_TARGET_PROPERTY(_x ... COMPILE_FLAGS)
is NOTFOUND :-/

But thank you Tyler for pointing me out the function. :-)

Best regards
Piotr Wyderski