How to add an additional option to dg-compile and dg-run

[Thomas Koenig]

Hi,

for the fortran-unsigned branch, I would like to be able to run all
existing Fortran tests also with -funsigned, to make sure the option
does not break anything on existing code.

Question is: How?

I came as far as

$ make check-fortran RUNTESTFLAGS="--target_board=unix/-funsigned"

but that causes testsuite failures because C does not recognize
the option.

Any other possibilites?

Best regards

	Thomas