package/libbpf: fix bpftrace build with kernel headers 5.{9, 10}

Buildroot added the bpftrace package in 2024 with commit
338acb27ff
which initially provided version 0.19.1.

This release includes upstream commit
fea3193989
which was added to version 0.17.0 in 2022 and makes use of certain
variables of struct bpf_btf_info which were added to the linux kernel in
2020 with version 5.11:
5329722057

+	__aligned_u64 name;
+	__u32 name_len;
+	__u32 kernel_btf;

The libbpf package updates toolchain headers with its bundled version
only when the toolchain headers are version 5.8 or older, this condition
is part of the initial version of the package added in 2020 with
buildroot commit f7b8508e4f. This version
limit should have been raised when the bpftrace package was added to
avoid build errors when the toolchain contains header versions 5.9 or
5.10.

This situation caused build errors in the autobuilder, the last one in
February 2025:

/home/autobuild/autobuild/instance-18/output-1/build/bpftrace-0.19.1/src/bpffeature.cpp:
 In member function 'bool bpftrace::BPFfeature::has_module_btf()':
/home/autobuild/autobuild/instance-18/output-1/build/bpftrace-0.19.1/src/bpffeature.cpp:573:8:
 error: 'struct bpf_btf_info' has no member named 'name'
  573 |   info.name = (__u64)name;
      |        ^~~~
/home/autobuild/autobuild/instance-18/output-1/build/bpftrace-0.19.1/src/bpffeature.cpp:574:8:
 error: 'struct bpf_btf_info' has no member named 'name_len'
  574 |   info.name_len = sizeof(name);

The problem disappeared from the autobuilders due to newer headers
versions used for the buildroot toolchain or other build errors occurring
earlier, like llvm version mismatches.

The build error can today still be reproduced with this defconfig

BR2_aarch64=y
BR2_KERNEL_HEADERS_5_10=y
BR2_TOOLCHAIN_BUILDROOT_CXX=y
BR2_PER_PACKAGE_DIRECTORIES=y
BR2_PACKAGE_BPFTRACE=y

on the 2026.02.x branch as of 0be927b89a.

To fix the problem we raise the BR2_TOOLCHAIN_HEADERS_AT_LEAST_ version
number.

Fixes:
https://autobuild.buildroot.net/results/dbe/dbecf88c7edba357cee8fea31294ddb9f4d188ad/
https://autobuild.buildroot.net/results/df5/df59e038de47f63d14e1be7bd12dd16a69636f79/
https://autobuild.buildroot.net/results/359/3595d39dd53a686bbf996dd4e532ced44906b9e3/
https://autobuild.buildroot.net/results/e4f/e4f95a5f30a605eadb81802075ea6bb1e2880684/
https://autobuild.buildroot.net/results/bd0/bd075cb8c55f9f8a017711dc804b8d81ae89b4c5/

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>

package/libbpf/libbpf.mk

@@ -18,13 +18,14 @@ define LIBBPF_BUILD_CMDS
 		-C $(@D)/src
 endef
 
-# bpf/bpf.h installed by libbpf uses bpf_iter_link_info that was added since
-# kernel 5.9, so we need to update some uapi headers in STAGING_DIR if the
-# toolchain is build with linux-headers < 5.9.
-# Otherwise bpf/bpf.h is broken due to out of date linux/bpf.h installed by the
-# toolchain.
-# https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a5cbe05a6673b85bed2a63ffcfea6a96c6410cff
-ifeq ($(BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_9),)
+# bpftrace uses variables from bpf_btf_info that were added since kernel
+# 5.11, so we need to update some uapi headers in STAGING_DIR if the
+# toolchain is build with linux-headers < 5.11.
+# Otherwise bpftrace is broken due to out of date linux/bpf.h installed
+# by the toolchain.
+# https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5329722057d41aebc31e391907a501feaa42f7d9
+# https://github.com/bpftrace/bpftrace/commit/fea31939899db48fa6d28f5ce880bfc39250ec9f
+ifeq ($(BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_11),)
 LIBBPF_UPDATE_UAPI_HEADERS = install_uapi_headers UAPIDIR=/usr/include/bpf
 
 define LIBBPF_FIX_STAGING_PC