• Needs pyproject.toml to declare build-time dependency on cysignals cypari2#93 (Needs pyproject.toml to declare build-time dependency on cysignals)
• merge cypari and cypari2 cypari2#19 (comment) (merge cypari, cypari2)
• Replace compile-time dependency on pari by run-time dispatch cysignals#125 (replace cysignal's optional PARI dependency by a general hook)

Tickets:

• cysignals: Replace compile-time dependency on pari by run-time dispatch #32431 cysignals: Replace compile-time dependency on pari by run-time dispatch

CC: @videlec @NathanDunfield @dimpase @kliem

Component: packages: standard

Issue created by migration from https://trac.sagemath.org/ticket/32360