[CMake] add_custom_command dependencies from file?

[Evgeniy Dushistov]

Hi,

I need to solve problem described here:

https://cmake.org/pipermail/cmake/2005-August/007091.html

Basically I have test.i (swig input):

%module native
%include "lib.hpp"
%{
#include "lib.hpp"
 %}

swig with -M option can tell that generated by it code depend on
"lib.hpp", but how I can reuse this data, can add_custom_command
accept input from file, not from variable? Is something changed till
2005?