[Libguestfs] [RHEL] nbdkit & libnbd for RHEL AV 8.3.0

Some thoughts on nbdkit and libnbd in RHEL Advanced Virtualization 8.3.0. We have two bugs open for rebases: * https://bugzilla.redhat.com/show_bug.cgi?id=1809231 "Rebase nbdkit to at least 1.18+ in RHEL AV 8.3.0" * https://bugzilla.redhat.com/show_bug.cgi?id=1809674 "Rebase libnbd for RHEL-AV 8.3.0" The rules for rebasing are (well, these are _my_ rules): (1) Must not introduce API/ABI incompatibility or regressions. (2) Must introduce worthwhile new features relevant to RHEL customers. (3) Must maintain any backported features from earlier RHEL. For nbdkit it makes sense to rebase to 1.18 since there are significant features relevant to virt-v2v (see my summary in https://bugzilla.redhat.com/show_bug.cgi?id=1809231#c1). So for nbdkit I have added a rhel-8.3 branch upstream, currently based on nbdkit 1.18.2. Since upstream 1.18.2 contains everything that was backported to RHEL AV 8.2 there is no need for any backports at this time. I should note that RHEL has never shipped the ext2 plugin, so the fact it was deprecated upstream (replaced with Eric's new ext2 filter) is irrelevant to RHEL. For libnbd, there are not really any significant features upstream, but the Golang bindings (not upstream yet) have been requested for RHEL (https://bugzilla.redhat.com/1814538). I think we can easily do this without rebasing, but with a cherry pick of these bindings. If there's anything I've missed, let me know. This situation could evolve as we get further requests. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW