Debian and Fedora package lcalc (Fedora calls the package L-function-devel). On Debian one needs packages liblfunction-dev and lcalc.

One needs to check how well-patched they are.

We had to introduce an env. var. SAGE_LCALC_INCDIR_NOLIBPREFIX to deal with the discrepancy in the include names, which is libLfunction/ on sage-dist, but Lfunction/ on Debian.

if SAGE_LCALC_INCDIR_NOLIBPREFIX is not '' then we assume that
the include prefix is Lfunction/, and otherwise it is
libLfunction/.

CC: @embray @isuruf @antonio-rojas @kiwifb

Component: build: configure

Author: Dima Pasechnik

Branch: 6aa7e76

Reviewer: Isuru Fernando

Issue created by migration from https://trac.sagemath.org/ticket/28224