libgfortran: Adjust bytes_left and pos for access="STREAM".

During tab edits, the pos (position) and bytes_used
Variables were not being set correctly for stream I/O.
Since stream I/O does not have 'real' records, the
format buffer active length must be used instead of
the record length variable.

       PR libgfortran/109358

libgfortran/ChangeLog:

	* io/transfer.c (formatted_transfer_scalar_write): Adjust
	bytes_used and pos variable for stream access.

gcc/testsuite/ChangeLog:

	* gfortran.dg/pr109358.f90: New test.

gcc/testsuite/gfortran.dg/pr109358.f90

@@ -0,0 +1,14 @@
+! { dg-do run }
+! PR109358, test that tabs during stream io are correct.
+program tabs
+  implicit none
+  integer :: fd
+  character(64) :: line
+  open(newunit=fd, file="otabs.txt", form="formatted", access="stream")
+  write(fd, "(i4, t40, i4, t20, i5.5)") 1234, 5555, 67890
+  close(fd)
+  open(newunit=fd, file="otabs.txt", form="formatted")
+  read(fd,"(a)") line
+  close(fd, status='delete')
+  if (line .ne. "1234               67890               5555") stop 10
+end program tabs

libgfortran/io/transfer.c

@@ -2072,11 +2072,11 @@ formatted_transfer_scalar_write (st_parameter_dt *dtp, bt type, void *p, int kin
 	  dtp->u.p.skips = dtp->u.p.pending_spaces = 0;
 	}
 
-      bytes_used = dtp->u.p.current_unit->recl
-		   - dtp->u.p.current_unit->bytes_left;
-
       if (is_stream_io(dtp))
-	bytes_used = 0;
+	bytes_used = dtp->u.p.current_unit->fbuf->act;
+      else
+	bytes_used = dtp->u.p.current_unit->recl
+		    - dtp->u.p.current_unit->bytes_left;
 
       switch (t)
 	{
@@ -2452,7 +2452,11 @@ formatted_transfer_scalar_write (st_parameter_dt *dtp, bt type, void *p, int kin
 	  p = ((char *) p) + size;
 	}
 
-      pos = dtp->u.p.current_unit->recl - dtp->u.p.current_unit->bytes_left;
+      if (is_stream_io(dtp))
+	pos = dtp->u.p.current_unit->fbuf->act;
+      else
+	pos = dtp->u.p.current_unit->recl - dtp->u.p.current_unit->bytes_left;
+
       dtp->u.p.max_pos = (dtp->u.p.max_pos > pos) ? dtp->u.p.max_pos : pos;
     }