For some unknown reason, macos-15 runners (which macos-latest
resolves to currently) seem to be consistently 25-40% slower than
macos-14 runners; the "macos" job (doing an universal binary build
for 2 architectures, with LTO) often take over 5 hours, and have
reached the 6 hour timeout once.
Switch this back to macos-14 to speed it up and reduce the risk of
hitting the timeout.
In the future, if/when the macos-14 runners are phased out, and if
the performance reduction in macos-15 runners remains, we'd need to
switch to building each architecture in a separate job, and merge
them together separately if we still want to provide universal
binaries.
Martin Storsjö
1a25a0ff74