libbpf: Fix anonymous type check in CO-RE logic

Use type name for checking whether CO-RE relocation is referring to
anonymous type. Using spec string makes no sense.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220426004511.2691730-2-andrii@kernel.org

tools/lib/bpf/relo_core.c

@@ -1207,7 +1207,7 @@ int bpf_core_calc_relo_insn(const char *prog_name,
 	}
 
 	/* libbpf doesn't support candidate search for anonymous types */
-	if (str_is_empty(spec_str)) {
+	if (str_is_empty(local_name)) {
 		pr_warn("prog '%s': relo #%d: <%s> (%d) relocation doesn't support anonymous types\n",
 			prog_name, relo_idx, core_relo_kind_str(relo->kind), relo->kind);
 		return -EOPNOTSUPP;