libbpf: Add enum64 support for bpf linking

Add BTF_KIND_ENUM64 support for bpf linking, which is
very similar to BTF_KIND_ENUM.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220607062642.3721494-1-yhs@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/lib/bpf/linker.c

@@ -1335,6 +1335,7 @@ static bool glob_sym_btf_matches(const char *sym_name, bool exact,
 	case BTF_KIND_STRUCT:
 	case BTF_KIND_UNION:
 	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
 	case BTF_KIND_FWD:
 	case BTF_KIND_FUNC:
 	case BTF_KIND_VAR:
@@ -1357,6 +1358,7 @@ static bool glob_sym_btf_matches(const char *sym_name, bool exact,
 	case BTF_KIND_INT:
 	case BTF_KIND_FLOAT:
 	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
 		/* ignore encoding for int and enum values for enum */
 		if (t1->size != t2->size) {
 			pr_warn("global '%s': incompatible %s '%s' size %u and %u\n",