libbpf: Stop using to-be-deprecated APIs

Remove all the internal uses of libbpf APIs that are slated to be
deprecated in v0.7.

Signed-off-by: Andrii Nakryiko <[e-mail]>
Signed-off-by: Alexei Starovoitov <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

tools/lib/bpf/libbpf.c

···
 	return 0;
 
 err_unpin_maps:
-	while ((map = bpf_map__prev(map, obj))) {
+	while ((map = bpf_object__prev_map(obj, map))) {
 		if (!map->pin_path)
 			continue;
 
···
 	return 0;
 
 err_unpin_programs:
-	while ((prog = bpf_program__prev(prog, obj))) {
+	while ((prog = bpf_object__prev_program(obj, prog))) {
 		char buf[PATH_MAX];
 		int len;
 
···
 	return 0;
 }
 
+static int bpf_program_nth_fd(const struct bpf_program *prog, int n);
+
 int bpf_program__fd(const struct bpf_program *prog)
 {
-	return bpf_program__nth_fd(prog, 0);
+	return bpf_program_nth_fd(prog, 0);
 }
 
 size_t bpf_program__size(const struct bpf_program *prog)
···
 	return 0;
 }
 
-int bpf_program__nth_fd(const struct bpf_program *prog, int n)
+__attribute__((alias("bpf_program_nth_fd")))
+int bpf_program__nth_fd(const struct bpf_program *prog, int n);
+
+static int bpf_program_nth_fd(const struct bpf_program *prog, int n)
 {
 	int fd;