This ticket adds an spkg-configure.m4 for libhomfly, in order to use it from a system package if possible (see #27330).

No problem detected with this one: Sage builds flawlessy with the system package on FreeBSD, and the platforms tested on GH Actions.

Depends on #28991
Depends on #30626

CC: @tscrim @orlitzky @dimpase @sheerluck

Component: build: configure

Keywords: libhomfly, system packages

Author: Thierry Thomas, Dima Pasechnik

Branch/Commit: 6b90412

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/29630