[patch,fortran] Allow namelist with internal file (PR 28224)

[FX Coudert]

> From your build directory go down to gcc and do the make check- 
> gfortran there.

In that gcc/ directory, you can also run only certain tests, eg:

make check-gfortran RUNTESTFLAGS="dg.exp=gfortran.dg/io_contraints*.f90"

to run only the gfortran.dg/icontraints*.f90 tests (if there are any,  
I don't have a source code available where I am right now). Lots of  
other testsuite magic (like running all tests with sets of additional  
options) can be found on the GCC web page (doc, install, testing, IIRC).

FX