build-sys: add clean-python target

Building for a different version of Python requires removing all
build products for the old version. There's no nice way to do it,
short of doing 'make clean'. The new 'clean-python' target is a
bit hacky, but seems to work:
  ./configure PYTHON=python2 && make && make install
  make clean-python
  ./configure PYTHON=python3 --disable-gtk-doc --disable-man-pages && make && make install
should install modules for both versions of Python.

diff --git a/Makefile.am b/Makefile.am
index 5d35993..fdfdd65 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -4136,6 +4136,11 @@ CLEAN_LOCAL_HOOKS += clean-sphinx
 clean-sphinx:
        -rm -rf docs/html/python-systemd/
 
+# Remove Python stuff, e.g. to force rebuilding for a different Python version.
+clean-python:
+       -rm -rf src/python-systemd/.libs src/python-systemd/*.l[ao]
+       -rm -f _daemon.la id128.la _journal.la login.la _reader.la
+
 # ------------------------------------------------------------------------------
 substitutions = \
        '|rootlibexecdir=$(rootlibexecdir)|' \