compile fortran program with 2 compilers

I am trying to run a program wrote in fortran where the subroutine has been compiled with gfortran and the main program has been compiled with ifort:

Here the source code:

subroutine:

subroutine testsub
    implicit none
    integer icarte
    read(10,*) icarte
    write(*,*)icarte 
    return 
    end`

main code:

program test
    implicit none
    integer i
    open (unit=10, file="file_test")
    do i=1,6
       read(10,*)
    enddo
    call testsub
    close(10)
    end

and the file read is:

1
2
3
4
5
6
7 5 6 8
23

And then I compile like that:

gfortran -c testsub.f

ar rcs libtest.a testsub.o

ifort -o testexe test.f -L./ -ltest -L/.../gcc/4.7.1/lib64 -lgfortran

and I obtained:

At line 4 of file testsub.f (unit = 10, file = 'fort.10')
Fortran runtime error: End of file

It looks like the logical unit was not given to the subroutine. I should add a compilation option somewhere... but I don't really know what and where... And to respond to the question "what happens if I compile both files with the same compiler ?" : the program runs perfectly :)

So if anyone as any idea...

This won't work. When you open the file in the main program, somewhere in the bowels of the ifort library the file will be opened and some state associated with it stored. GFortran knows nothing about the internal state of the ifort runtime library, and tries to look up the unit in its own runtime library state, which obviously fails.