With g95 (not gfortran), I systematically obtain that kind of message when quitting a program:
Remaining memory: 30 bytes at 0907a2e0 allocated at line 88 of gtk.f90
Line 88 is:
We should deallocate it somewhere.
There is a deallocate(carg) commented out at the end of the subroutine. Should it just be uncommented?
deallocate(carg) added in gtk.f90, in my gtk2devel and gtk3devel branch.