kernel: add objtool to shared workdir when CONFIG_UNWINDER_ORC is set
Based on: https://patchwork.openembedded.org/patch/148047/
When x86_64 enables CONFIG_UNWINDER_ORC [ORC (Oops Rewind Capability)
unwinder for unwinding kernel stack traces], objtool is required to
generate the required information.
If we don't copy objtool to the shared workdir, out-of-tree modules
cannot generate object files.
For instance, meta-skeleton/hello-mod fails with:
| make[3]: *** No rule to make target 'tools/objtool/objtool', needed by ...
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
