fbac336391
PR libgfortran/19052 * libgfortran.h (options_t): Add stderr_unit. * io/io.h (error_stream): Declare. * io/open.c (new_unit): Do not terminate abnormally if opening file preconnected to stdin, stdout, or stderr. * io/unit.c (init_units): Initialize stderr_unit. * io/unix.c (error_stream): New function. * runtime/environ.c (GFORTRAN_STDERR_UNIT): New environment variable. From-SVN: r94090