Now that we are able to build our own test modules, also allow to use
cached modules so a) kernel headers are not required and b) distro
maintainers are happy. It's still need a "--disable-test-modules" in
the configure since the default is enabled.
There's no license problems anymore since all modules come from our own
repository, we ship the sources and the modules can be easily rebuilt.
This is for convenience for development and testing since we don't want
to needlessly cross-compile the modules. There's a README file
explaining the building process for those who want to update them.
These files are compiled from their respective .c and thus have LPGL
license.
This adds the needed infra to cross-compile modules so we can test them
in our testsuite. Right now we are only compiling mod-simple.ko for x86,
x86_64 and sparc64.
The makefiles are organized in a way it's easy to force a rebuild of a
module by calling the Makefile.arch directly and that allows the rule in
Makefile to not trigger in case we want to ship the modules
pre-compiled.