[CMake] Resetting CMAKE_Fortran_FLAGS for a specific file

[marco restelli]

Hi,
   I would like to reset CMAKE_Fortran_FLAGS for one specific file in
a project. I have tried

SET_SOURCE_FILES_PROPERTIES(my_file.f90 PROPERTIES COMPILE_FLAGS "-O0 -g")

but it appends the new flags keeping the old ones. How can reset these
flags? Specifically, I have some files for which I need to avoid any
error checking and any optimization, independently from the selected
compiler.

Thanks, regards,
   Marco