build/pkgs/sagelib/spkg-src: Use build

Author: Matthias Koeppe

build/pkgs/sagelib/spkg-src

@@ -4,7 +4,7 @@
 # This script is not used during build.
 #
 # HOW TO MAKE THE TARBALL:
-# ./sage --sh build/pkgs/sagelib/spkg-src
+# make python_build && ./sage --sh build/pkgs/sagelib/spkg-src
 
 if [ -z "$SAGE_ROOT" ] ; then
     echo >&2 "Error - SAGE_ROOT undefined ... exiting"
@@ -18,4 +18,4 @@ set -e
 cd "$SAGE_ROOT"/build/pkgs/sagelib
 
 cd src
-python3 -u setup.py --no-user-cfg sdist --dist-dir "$SAGE_DISTFILES"
+python3 -m build --sdist --outdir "$SAGE_DISTFILES"