Use a beta version of libbpf to unblock perf_buffer__buffer API

Summary: It turns out that perf_buffer API is only available in libbpf 0.2.0, which hasn't been released yet. To unblock katran, I grabbed the latest libbpf revision and created a temporary manifest. To avoid relying on this "beta" version libbpf on other projects only katran uses it. I'll make sure to remove it in favor of the official libbpf 0.2.0 once it's released.

Reviewed By: anakryiko

Differential Revision: D24156655

fbshipit-source-id: 32f6e04079a862fbfe96fd5475678cfa4ae1b3db

Author: xttjsn

build/fbcode_builder/manifests/katran

@@ -24,7 +24,7 @@ BUILD_TESTS=OFF
 [dependencies]
 folly
 fizz
-libbpf
+libbpf_0_2_0_beta
 libmnl
 zlib
 googletest

build/fbcode_builder/manifests/libbpf_0_2_0_beta

@@ -0,0 +1,26 @@
+[manifest]
+name = libbpf_0_2_0_beta
+
+[download]
+url = https://github.com/libbpf/libbpf/archive/b6dd2f2.tar.gz
+sha256 = 8db9dca90f5c445ef2362e3c6a00f3d6c4bf36e8782f8e27704109c78e541497
+
+# BPF only builds on linux, so make it a NOP on other platforms
+[build.not(os=linux)]
+builder = nop
+
+[build.os=linux]
+builder = make
+subdir = libbpf-b6dd2f2b7df4d3bd35d64aaf521d9ad18d766f53/src
+
+[make.build_args]
+BUILD_STATIC_ONLY=y
+
+# libbpf now requires uapi headers >= 5.8
+[make.install_args]
+install
+install_uapi_headers
+BUILD_STATIC_ONLY=y
+
+[dependencies]
+libelf