prereq-build: add check for stdlib

One way to solve the python3 dependency check is to install
python3-minimal instead of python3 on Debian based systems.
Unfortunately, this results in a fairly unusable python.

Added check for ntpath, which is how the issue originally presented
itself.

Signed-off-by: Rosen Penev <[email protected]>

include/prereq-build.mk

@@ -190,6 +190,10 @@ $(eval $(call TestHostCommand,python3-distutils, \
 	Please install the Python3 distutils module, \
 	$(STAGING_DIR_HOST)/bin/python3 -c 'from distutils import util'))
 
+$(eval $(call TestHostCommand,python3-stdlib, \
+	Please install the Python3 stdlib module, \
+	$(STAGING_DIR_HOST)/bin/python3 -c 'import ntpath'))
+
 $(eval $(call SetupHostCommand,file,Please install the 'file' package, \
 	file --version 2>&1 | grep file))