arm64, call-out: don't blank temporaries wired to any-reg.
arm64: have r10 in the same location on +-darwin.
Don't check for bounds in find/position on lists with safety 0.
Check for :start in find/position on lists.
Github actions: run on ubuntu-24.04 which has a newer sbcl.
Transform (= small-int float) and not just (= float small-int).
github actions: use a more recent sbcl host.
Compile on netbsd arm64 with sb-core-compression option.