55d554f5d1
make TARGETS=bpf kselftest fails with: Makefile:127: tools/build/Makefile.include: No such file or directory When the bpf tool make is invoked from tools Makefile, srctree is cleared and the current logic check for srctree equals to empty string to determine srctree location from CURDIR. When the build in invoked from selftests/bpf Makefile, the srctree is set to "." and the same logic used for srctree equals to empty is needed to determine srctree. Check building_out_of_srctree undefined as the condition for both cases to fix "make TARGETS=bpf kselftest" build failure. Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20190927011344.4695-1-skhan@linuxfoundation.org
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.