libbpf/libbpf v0.5.0 on GitHub

New features and user-space APIs:

libbpf_set_strict_mode() allowing to opt-in into backwards incompatible libbpf-1.0 changes. See "Libbpf: the road to 1.0" and "Libbpf 1.0 migration guide" for more details.
streamlined error reporting for low-level APIs, high-level error-returning APIs, and pointer-returning APIs (as a libbpf-1.0 opt-in);
"Light" BPF skeleton support;
BPF_PROG_TYPE_SYSCALL support;
BPF perf link support for kprobe, uprobe, tracepoint, and perf_event BPF programs;
BPF cookie support for kprobe, uprobe, tracepoint, and perf_event BPF programs through bpf_program__attach_[ku]probe_opts() APIs;
allow to specify ref_ctr_off for USDT semaphores through bpf_program__attach_uprobe_opts() API;
btf_custom_path support in bpf_object_open_opts, allowing to specify custom BTF for CO-RE relocations;
sk_reuseport/migrate program type support;
btf_dump__dump_type_data() API, allowing to dump binary data according to BTF type description;
btf__load_into_kernel() and btf__load_from_kernel_by_id(), and split BTF variants of them;
btf__load_vmlinux_btf() and btf__load_module_btf() APIs;
bpf_map__initial_value() API to get initial value of mmap-ed BPF maps;
bpf_map_lookup_and_delete_elem_flags() API.

support for weak typed __ksym externs;
BPF timer helpers: bpf_timer_init(), bpf_timer_set_callback(), bpf_timer_start(), bpf_timer_cancel();
bpf_get_attach_cookie() helper to get BPF cookie from BPF program side;
bpf_get_func_ip() helper;
bpf_sys_bpf() helper;
bpf_task_pt_regs() helper;
bpf_btf_find_by_name_kind() helper;
usability improvements for bpf_tracing.h when target architecture is missing.

improve BPF support detection on old Red Hat kernels with backported BPF patches;
improvements for LTO builds with GCC 10+;
pass NLM_F_EXCL when creating TC qdisc;
better support of BPF map reuse on old kernels;
fix the bug resulting in sometimes closing FD 0, which wasn't created and owned by libbpf itself.