Merge branch 'staging-next'

It's not perfect, but I think we can deal with the rest of the
regressions directly on master, so that this process does not stall.

pkgs/development/interpreters/python/hooks/setuptools-build-hook.sh

@@ -27,9 +27,9 @@ setuptoolsShellHook() {
     if test -e setup.py; then
         tmp_path=$(mktemp -d)
         export PATH="$tmp_path/bin:$PATH"
-        export PYTHONPATH="@pythonSitePackages@:$PYTHONPATH"
+        export PYTHONPATH="$tmp_path/@pythonSitePackages@:$PYTHONPATH"
         mkdir -p "$tmp_path/@pythonSitePackages@"
-        eval "@pythonInterpreter@ -m pip -e . --prefix $tmp_path >&2"
+        eval "@pythonInterpreter@ -m pip install -e . --prefix $tmp_path >&2"
     fi
 
     runHook postShellHook