delve ftbfs on amd64 due to bpftool

Actually it needs linux-tools for the running kernel. So it seems impossible to code it in debian/control as the running kernel version can't be predicted.

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 2021481

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

The bpftool is used in following command

`bpftool btf dump file /sys/kernel/btf/vmlinux format c`

Upstream statically encoded the generated output in source tree, https://github.com/go-delve/delve/blob/v1.20.2/pkg/proc/internal/ebpf/bpf/include/vmlinux.h

But the Debian package strips this vmlinux.h file and generates it at build time.

@Kernel team, what you think is more appreciated? If generating at build time, then we need a runnable bpftool command in build env.

I tried to call bpftool directly instead of using the /usr/sbin/bpftool script: https://git.launchpad.net/~danilogondolfo/ubuntu/+source/delve/commit/?h=ubuntu/devel&id=2cf86a5394786f9ec8b2931d0c4c05af992be1c2

It kinda worked but then the build failed with:

In file included from /<<PKGBUILDDIR>>/obj-x86_64-linux-gnu/src/github.com/go-delve/delve/pkg/proc/internal/ebpf/bpf/trace.bpf.c:1:
/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu/src/github.com/go-delve/delve/pkg/proc/internal/ebpf/bpf/include/trace.bpf.h:10:17: error: use of undeclared identifier 'BPF_MAP_TYPE_RINGBUF'
   __uint(type, BPF_MAP_TYPE_RINGBUF);
                ^
/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu/src/github.com/go-delve/delve/pkg/proc/internal/ebpf/bpf/include/trace.bpf.h:15:17: error: use of undeclared identifier 'BPF_MAP_TYPE_RINGBUF'
   __uint(type, BPF_MAP_TYPE_RINGBUF);
                ^
/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu/src/github.com/go-delve/delve/pkg/proc/internal/ebpf/bpf/trace.bpf.c:243:37: error: use of undeclared identifier 'BPF_RB_FORCE_WAKEUP'
    bpf_ringbuf_submit(parsed_args, BPF_RB_FORCE_WAKEUP);
                                    ^
3 errors generated.
Error: clang: exit status 1

Looks like pkg/proc/internal/ebpf/bpf/include/trace.bpf.h is missing a #include <linux/bpf.h>

Maybe there is a better solution than this hack...

This bug was fixed in the package delve - 1.21.0-1

---------------
delve (1.21.0-1) unstable; urgency=medium

  * New upstream version 1.21.0
    + Read debug info file from correct directory in trace
      command (Closes: #1037284)
  * Don't generate vmlinux.h with bpftool (LP: #2021481)
    bpftool is not functional on Ubuntu builder
  * Bump golang-starlark-dev to 0.0~git20230726.7dadff3
  * Bump golang-github-google-go-dap-dev to 0.10.0

 -- Shengjing Zhu <email address hidden> Fri, 28 Jul 2023 22:00:15 +0800

It looks like this issue was fixed in delve.