As written, the Makefile isn’t adding any OpenACC compiler flags to the compilation, only the link. In the example Makefile you based this on, they put these flags as part of the compiler variable. Instead, I’d recommend adding an “OPT” variable.
F90=pgfortran
OPT=-acc -Minfo=accel
# -------------------End-macro-Defs---------------------------
# Here is the link step
EMUNE3D:Objects.obj Global_variables.obj module_precision.obj Input_subroutines.obj Horizon.obj Get_family.obj damage.obj peri_motion.obj dynamics.obj Solver.obj EMUNE3D.obj
$(F90) $(OPT) -o EMUNE3D Objects.obj Global_variables.obj module_precision.obj Input_subroutines.obj Horizon.obj Get_family.obj damage.obj peri_motion.obj dynamics.obj Solver.obj EMUNE3D.obj
# Here are the compile steps
module_precision.obj:./module_precision.f90
$(F90) $(OPT) -c ./module_precision.f90
# Here are the compile steps
....