How to set -Werror=bar in the backend?

[Georg-Johann Lay]

Hi,

I'd like to automatically turn on a warning option in
the backend's C file, i.e. some option logic like

-mfoo automatically turns on -Werror=bar.

(self)specs is not a good solution because that leads to confusing
behaviour, e.g. if the command line has -Wno-error=bar etc.

To turn on the diagnostic, I'd like to use

opts-common.c:control_warning_option()

The problem with control_warning_option() is that
I have no idea how to get the parameters
    struct cl_option_handlers *handlers
    unsigned int lang_mask
needed by that function.

opts.c:target_handle_option() knows all these values but does
not pass them down to targetm.handle_option() so that these
values are missing there.

How can I get these values in targetm.handle_option()?

Thanks,

Johann