[libvirt] RFC: spec file cleanup ideas

[Cole Robinson]

Hi all,

I wanted to float some ideas about cleaning up the RPM spec file. None of it
is urgent but I'll end up scratching the itch eventually and I want to make
sure people are on board

Old distro bits:

* Drop support for building on rhel5... this was ACKd previously by eblake:
http://www.redhat.com/archives/libvir-list/2015-November/msg00175.html

* Drop support for end-of-life Fedora. There's lots of Fedora conditionals
going back to Fedora 13. I don't think it's really interesting to try to
support building an RPM on a distribution that is no longer receiving updates.
But we could be a bit conservative and give a couple release window, dropping
support for less than Fedora 20 for example (which went EOL in June 2015)

Configuration variables: some of these could still feasibly be 'useful' even
if they aren't programmatically set by any distro conditional, but I think
unless someone actively uses them we should seek to have as few conditionals
as possible, rather than conditionalize everything by default which seems more
common. Some ideas:

* Drop with_* conditionals that are only used by old Fedora or RHEL5. I didn't
audit all of them but the obvious ones are straight forward like:
with_systemd_macros, with_polkit, with_capng, with_netcf, with_yajl,
with_capng, with_avahi, with_hal/all HAL support

* Drop client_only/server_drivers/with_libvirtd ... do these serve any good
purpose? (once the rhel5 bits are gone)

* Drop with_driver_modules: it's unconditionally enabled and has been since it
was introduced


Old spec bits cleanup:

* drop defattr(), it's long since not needed
* drop manual removal of the buildroot, it's long since not needed
* use %global consistently instead of %define
* consider using %{with/without X} pattern instead of defining variables as with_X

* The top of the spec has this block:

# If neither fedora nor rhel was defined, try to guess them from dist
%if !0%{?rhel} && !0%{?fedora}
%{expand:%(echo "%{?dist}" | \
  sed -ne 's/^\.el\([0-9]\+\).*/%%define rhel \1/p')}
%{expand:%(echo "%{?dist}" | \
  sed -ne 's/^\.fc\?\([0-9]\+\).*/%%define fedora \1/p')}
%endif

Is it actually still relevant? It was added 5 years ago... I don't know in
what case rhel or fedora macros won't be defined