samples/bpf: Add missing header

Include unistd.h to define __NR_getuid and __NR_getsid.

Signed-off-by: Mickaël Salaün <[email protected]>
Acked-by: Joe Stringer <[email protected]>
Acked-by: Wang Nan <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

samples/bpf/tracex5_kern.c

@@ -8,6 +8,7 @@
 #include <linux/version.h>
 #include <uapi/linux/bpf.h>
 #include <uapi/linux/seccomp.h>
+#include <uapi/linux/unistd.h>
 #include "bpf_helpers.h"
 
 #define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F