The llvm-bpf-$version.tar.xz might be absent. For example `make clean` executed, CONFIG_TARGET changed.
This commit can only guarantee that the target file can be built when tools/compile is explicitly called rather than $(tools/stamp-compile).
Signed-off-by: Huangbin Zhan <zhanhb88@gmail.com>
This can be used for adding the toolchain to an existing tree without having
to build it from scratch.
Enable building the toolchain + tarball by default on buildbot
Signed-off-by: Felix Fietkau <nbd@nbd.name>