See
GNU make[
^].
However, the shown
Makefile will create the
snap7.dll and
snap7.lib. If you have executed that using
make all
, there is no need to compile the source files (
snap_*.cpp) again in your Qt project. Instead just add the library to your Qt project with the correct path:
win32:LIBS += <snap7_make_output_path>/snap7.lib
and remove the
snap7 source and header files.