src/setup.py, src/sage/env.py (sage_include_directories): Do not add another copy of SAGE_INC, SAGE_LOCAL/lib to include dirs, library dirs #29697
Description
$SAGE_LOCAL/{include,lib} are already added to the front of the search paths CPATH and LIBRARY_PATH by sage-env.
We remove code that adds another copy. This removes a dependency on SAGE_LOCAL during the build of sagelib.
The function sage_include_directories, apart from its use by setup.py, is also used by sage.misc.cython.cython.
CC: @dimpase @kiwifb @orlitzky @isuruf
Component: build
Author: Matthias Koeppe
Branch: 9a50cba
Reviewer: François Bissey
Issue created by migration from https://trac.sagemath.org/ticket/29697