clang -g -O2 -Wall -I. -c xdp-proxy.c -o xdp-proxy.o
clang -Wall -O2 -g xdp-proxy.o -static -lbpf -lelf -lz -o xdp-proxy

These two instructions cannot run

xdp-proxy.c:54:2: warning: implicit declaration of function 'LIBBPF_OPTS' is invalid in C99 [-Wimplicit-function-declaration]
LIBBPF_OPTS(bpf_xdp_attach_opts, attach_opts);
^
xdp-proxy.c:54:14: error: use of undeclared identifier 'bpf_xdp_attach_opts'
LIBBPF_OPTS(bpf_xdp_attach_opts, attach_opts);
^
xdp-proxy.c:54:35: error: use of undeclared identifier 'attach_opts'
LIBBPF_OPTS(bpf_xdp_attach_opts, attach_opts);
^
xdp-proxy.c:55:8: warning: implicit declaration of function 'bpf_xdp_attach' is invalid in C99 [-Wimplicit-function-declaration]
err = bpf_xdp_attach(ifindex, prog_id, xdp_flags, &attach_opts);
^
xdp-proxy.c:55:53: error: use of undeclared identifier 'attach_opts'
err = bpf_xdp_attach(ifindex, prog_id, xdp_flags, &attach_opts);
^
xdp-proxy.c:67:2: warning: implicit declaration of function 'bpf_xdp_detach' is invalid in C99 [-Wimplicit-function-declaration]
bpf_xdp_detach(ifindex, xdp_flags, &attach_opts);
^
xdp-proxy.c:67:38: error: use of undeclared identifier 'attach_opts'
bpf_xdp_detach(ifindex, xdp_flags, &attach_opts);
^
3 warnings and 4 errors generated.

https://github.com/feiskyer/ebpf-apps/blob/main/bcc-apps/python/execsnoop.c#L2 includes uapi/linux/ptrace.h header file,

i switch it to linux/ptrace.h, it work,

even remove linux/ptrace.h, it work.

Is the include file useless?