Added a script to update all config.guess and config.sub.

[Darelelve]

An update-configs.sh script was added to update all config.guess and config.sub files, because in some sources these configuration files were too old and did not know about new architectures (for example, RISC-V).

[flavioc]

Should we just run autoreconf -fi in the packages with stale files? How many packages have problems?

[Darelelve]

I checked all packages from src and .cache/cross-hurd, and the following packages are problematic (there may be more, but I'm not sure):
libdaemon-0.14 (config.guess timestamp='2008-01-23'), pkg-config-lite-0.28-1 (2009-12-30), libuuids-1.0.3 (2012-12-29), dde and hurd (2013-02-12), flex-2.6.4 (2015-08-20), gmp-6.3.0 (had no timestamp field at all), and rumpkernel in the buildrump.sh/src/sys/external/isc/libsodium/dist folder (2013-06-10). For all packages except rumpkernel, the autoreconf -fi command updated config.guess to timestamp='2022-01-09', while rumpkernel retained the same version.