package/python-xmodem: add host variant

The host variant of python-xmodem will be needed by Snagboot, so this
commit enables it. We also add a very simple test case that simply
makes sure we can import the module. Testing xmodem more extensively
is difficult without an actual serial port to open.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

support/testing/tests/package/test_python_xmodem.py

@@ -0,0 +1,9 @@
+import infra.basetest
+
+
+class TestHostPythonXmodem(infra.basetest.BRHostPkgTest):
+    hostpkgs = ["host-python-xmodem"]
+
+    def test_run(self):
+        cmd = ["host/bin/python3", "-c", "import xmodem"]
+        infra.run_cmd_on_host(self.builddir, cmd)