disable setuid configure checks

disable setuid configure checks

For some strange reason, when running reprotest test on salsa-ci,
which apparently is running as root, - on the *second* build only
the configure fails (after successfully built package the first
time). The configure test tries to change gid and verifies it
actually changed (not that the syscall exist), - and that fails.
Since it is extremely uncommon to configure the build process as
root, salsa-ci test environment details are quite deep down the line,
and we know the syscall actually works, just disable the probe,
pretending we are not root.

Gbp-Pq: Name disable-setuid-confchecks.patch