Some of my programs need this option, but I finally found out that it is not
working. -d makes no difference in the print out of the c routine, but it should  -

[dir:~/tests/gfortran] dir% gfortran -c ptran.f
[dir:~/tests/gfortran] dir% cc -c cend.c
[dir:~/tests/gfortran] dir% gfortran -o ptran ptran.o cend.o
[dir:~/tests/gfortran] dir% ptran
cend 10 20 10 20 
STOP 0
[dir:~/tests/gfortran] dir% gfortran -d8 -c ptran.f
[dir:~/tests/gfortran] dir% gfortran -o ptran ptran.o cend.o
[dir:~/tests/gfortran] dir% ptran
cend 10 20 10 20 
STOP 0
[dir:~/tests/gfortran] dir% cat ptran.f
      program ptran
      ixmin = 10
      iymin = 10
      ixmax = 20
      iymax = 20
      call cend(ixmin,ixmax,iymin,iymax)
      stop
      end
[dir:~/tests/gfortran] dir% cat cend.c
int cend_(long *ixmin,long *ixmax,long *iymin,long *iymax)
{
    printf("cend %ld %ld %ld %ld \n",*ixmin,*ixmax,*iymin,*iymax);
    return 0;
}