-mtls-dialect=gnu2

[Thomas Klausner <wiz%netbsd.org@localhost>]

Hi!

The in-tree gcc supports '-mtls-dialect=gnu2', so configure scripts
that check if it exists and returns an error succeed because it exists
and doesn't return an error.

However, when running the resulting files on NetBSD, one gets:

    Unsupported relocation type 36 in non-PLT relocations

because the linker doesn't support this.

I recently saw this in py-pikepdf where the flag came from
py-nanobind. I've filed a bug report and upstream now changed it to
only check for that flag on Linux. [1] So the problem that led me here
is fixed.

But I wonder: Is there something more we should do in NetBSD about
this?  I.e. add support for that relocation type, or stop accepting
the flag in our in-tree gcc?

Cheers,
 Thomas

[1] https://github.com/wjakob/nanobind/issues/1461