glibc: define __NR_bpf

Generating BTF during kernel builds involves building host libbpf,
which fails unless __NR_bpf is defined.

Bug: 203823368
Test: build android-mainline kernel with CONFIG_DEBUG_INFO_BTF=y
Signed-off-by: Connor O'Brien <connoro@google.com>
Change-Id: I3a01b37b2f3dce3797357467a77b78b69ebe8cd9
3 files changed