Enable building multiple test programs and related kernel modules, with
initial support for the bpf_testmod.ko module required since kernel 6.4.
Explicitly disable LTO and clean up makefile variables and formatting.
Fix a musl-related build failure by adding a kernel 6.6 patch:
360-selftests-bpf-portability-of-unprivileged-tests.patch
Signed-off-by: Tony Ambardar <itugrok@yahoo.com>
708e6b840e