Index: head/audio/oss/files/patch-kernel_OS_FreeBSD_os__freebsd.c
===================================================================
--- head/audio/oss/files/patch-kernel_OS_FreeBSD_os__freebsd.c	(revision 520255)
+++ head/audio/oss/files/patch-kernel_OS_FreeBSD_os__freebsd.c	(revision 520256)
@@ -1,18 +1,35 @@
 --- kernel/OS/FreeBSD/os_freebsd.c.orig	2019-03-06 07:52:21 UTC
 +++ kernel/OS/FreeBSD/os_freebsd.c
-@@ -920,15 +920,9 @@ oss_poll (struct cdev *bsd_dev, int events, struct thr
+@@ -15,6 +15,8 @@
+ #include "oss_config.h"
+ #include "midi_core.h"
+ #include <oss_pci.h>
++#include <sys/param.h>
++#include <sys/types.h>
+ #include <sys/conf.h>
+ #include <sys/module.h>
+ #include <sys/proc.h>
+@@ -25,6 +28,7 @@
+ #include <sys/poll.h>
+ #include <sys/param.h>
+ #include <sys/filio.h>
++#include <sys/systm.h>
+ 
+ /* Function prototypes */
+ static d_open_t oss_open;
+@@ -920,15 +923,9 @@ oss_poll (struct cdev *bsd_dev, int events, struct thr
    return ev.revents;
  }
  
 -#if defined(D_VERSION_03) && (D_VERSION == D_VERSION_03)
  static int
  oss_mmap (struct cdev *bsd_dev, vm_ooffset_t offset, vm_paddr_t * paddr,
  	  int nprot, vm_memattr_t *memattr)
 -#else
 -static int
 -oss_mmap (struct cdev *bsd_dev, vm_offset_t offset, vm_paddr_t * paddr,
 -	  int nprot)
 -#endif
  {
    int retval;
    int dev;