When calling python tools to convert misra documentation or merge
cppcheck xml files, use $(PYTHON).
While there fix misra document conversion script to be executable.
Fixes: 57caa5375321 ("xen: Add MISRA support to cppcheck make rule") Fixes: 43aa3f6e72d3 ("xen/build: Add cppcheck and cppcheck-html make rules") Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com> Acked-by: Jan Beulich <jbeulich@suse.com>