Add GSI-OpenSSH 9.9 from Fedora 42 current stable

[fscheiner]

The changes are based on:

https://kojipkgs.fedoraproject.org//packages/gsi-openssh/9.9p1/6.fc42/src/gsi-openssh-9.9p1-6.fc42.src.rpm

[fscheiner]

@msalle, @ellert, @maarten-litmaath:

So here's the PR for our new in-tree GSI-OpenSSH based on the version currently in Fedora 42 (aka stable).
Getting here took unnecessarily long, sorry for that.

Special thanks go to @ellert for updating the HPN version to 18.6. I wondered multiple times over code removals when patching the code up for inclusion. But I didn't notice until testing that this uses a newer HPN version than before. :-)

This is so far only tested on Rocky Linux 8, testing on other distros is welcome, also if just tested to build and install there.

Rocky Linux 8

[johndoe@gridftp-5 gsi-openssh-9.9p1-testing]$ sudo ~/bin/test-gss-kex-for-gsi-openssh.bash gridftp-5.machine-hall.org johndoe2
gsisshd: OpenSSH_9.9p1c-GSI_hpn18.6.0 GSI, OpenSSL 1.1.1k  FIPS 25 Mar 2021
gsissh: OpenSSH_9.9p1c-GSI_hpn18.6.0 GSI, OpenSSL 1.1.1k  FIPS 25 Mar 2021

Wait 3 seconds for startup of gsisshd ...

gss-gex-sha1- OK ( plus johndoe => johndoe2 )
gss-group1-sha1- OK ( plus johndoe => johndoe2 )
gss-group14-sha256- OK ( plus johndoe => johndoe2 )
gss-nistp256-sha256- OK ( plus johndoe => johndoe2 )
gss-curve25519-sha256- OK ( plus johndoe => johndoe2 )
gss-group16-sha512- OK ( plus johndoe => johndoe2 )