samples/seccomp: fix dependencies on arch macros
Will Drewry authored
This change fixes the compilation error reported for
i386 allmodconfig here:
  http://kisskb.ellerman.id.au/kisskb/buildresult/6123842/



Logic attempting to predict the host architecture has been
removed from the Makefile.  Instead, the bpf-direct sample
should now compile on any architecture, but if the architecture
is not supported, it will compile a minimal main() function.

This change also ensures the samples are not compiled when
there is no seccomp filter support.
Reported-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Suggested-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarWill Drewry <wad@chromium.org>
05acc0b6