kern_rctl.c: Minimal includes when RCTL not defined

If RCTL is not defined, only the system call stubs returning ENOSYS are
compiled in.  In this case, don't waste time including most headers
since their code is not used.

Reviewed by:    markj
MFC after:      2 weeks
Sponsored by:   The FreeBSD Foundation

sys/kern/kern_rctl.c

@@ -28,6 +28,8 @@
  * SUCH DAMAGE.
  */
 
+#ifdef RCTL
+
 #include <sys/cdefs.h>
 #include <sys/param.h>
 #include <sys/devctl.h>
@@ -56,7 +58,6 @@
 #include <sys/tree.h>
 #include <vm/uma.h>
 
-#ifdef RCTL
 #ifndef RACCT
 #error "The RCTL option requires the RACCT option"
 #endif
@@ -2204,6 +2205,9 @@ rctl_init(void)
 
 #else /* !RCTL */
 
+#include <sys/types.h>
+#include <sys/sysproto.h>
+
 int
 sys_rctl_get_racct(struct thread *td, struct rctl_get_racct_args *uap)
 {
@@ -2239,4 +2243,4 @@ sys_rctl_remove_rule(struct thread *td, struct rctl_remove_rule_args *uap)
 	return (ENOSYS);
 }
 
-#endif /* !RCTL */
+#endif /* RCTL */