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>
