Problem compiling NONMEM with mingw gfortran 4.3.0 builds

[Steve Chapel]

Steve Chapel wrote:
> After fixing all executables and libraries to use gfortran, the 
> program compiled and ran, but I got a Fortran runtime error: Bad file 
> descriptor. It also shows the offending source code line as "(unit=29, 
> file='CONOUT$')". Should CONOUT$ be con instead?

My problems with gfortran now boil down to a problem demonstrated by the 
following program:

       character*72 fnint
       data fnint /'con'/
       i=index(fnint,' ');
       open(unit=29,file=fnint(1:i-1))
       write(29,100)
100    format('1Hello, world!')
       end

C At line 4 of file bug.for (unit = 29, file = '')
C Fortran runtime error: File 'con' does not exist

This is a pared-down example that shows the error I'm getting with 
NONMEM. Basically, fnint is a character string that defines where output 
should go. Can someone point out a bug in the above code, and show how I 
can get the desired result? Or is this a bug in gfortran?

Thanks,
Steve