Several run time paths in the python library are hardwired, in most cases to $SAGE_LOCAL.
$SAGE_LOCAL has no meaning outside of Sage (the distribution). So it's better to add them to sage-env.py and make them overridable.

For example in libs.singular.singular_init, the singular shared object is looked for in $SAGE_LOCAL/lib.

CC: @jondo @kiwifb @mkoeppe @dimpase @vbraun @kcrisman @miguelmarco @nbruin

Component: build

Keywords: environment, SAGE_LOCAL, hardwired, run time

Author: Felix Salfelder, Erik Bray, Matthias Koeppe

Branch: 45c5dd0

Reviewer: Jeroen Demeyer

Issue created by migration from https://trac.sagemath.org/ticket/15105