diff --git a/sys/contrib/ipfilter/netinet/ip_frag.c b/sys/contrib/ipfilter/netinet/ip_frag.c
index 80cd5eccaa7..f0459da18b0 100644
--- a/sys/contrib/ipfilter/netinet/ip_frag.c
+++ b/sys/contrib/ipfilter/netinet/ip_frag.c
@@ -34,11 +34,11 @@
 #include <sys/socket.h>
 #if defined(_KERNEL)
 # include <sys/systm.h>
-# if !defined(__SVR4) && !defined(__svr4__)
+# if !defined(__SVR4)
 #  include <sys/mbuf.h>
 # endif
 #endif
-#if !defined(__SVR4) && !defined(__svr4__)
+#if !defined(__SVR4)
 # if defined(_KERNEL)
 #  include <sys/kernel.h>
 # endif
diff --git a/sys/contrib/ipfilter/netinet/ip_proxy.h b/sys/contrib/ipfilter/netinet/ip_proxy.h
index 832a379c9f8..659b0a7ebe2 100644
--- a/sys/contrib/ipfilter/netinet/ip_proxy.h
+++ b/sys/contrib/ipfilter/netinet/ip_proxy.h
@@ -13,14 +13,14 @@
 #define	__IP_PROXY_H__
 
 #ifndef	SOLARIS
-# if defined(sun) && (defined(__svr4__) || defined(__SVR4))
+# if defined(sun) && defined(__SVR4))
 #  define	SOLARIS		1
 # else
 #  define	SOLARIS		0
 # endif
 #endif
 
-#if defined(__STDC__) || defined(__GNUC__) || defined(_AIX51)
+#if defined(__STDC__) || defined(__GNUC__)
 #define	SIOCPROXY	_IOWR('r', 64, struct ap_control)
 #else
 #define	SIOCPROXY	_IOWR(r, 64, struct ap_control)
diff --git a/sys/contrib/ipfilter/netinet/ip_rules.c b/sys/contrib/ipfilter/netinet/ip_rules.c
index 18654f89f64..2fb61e9d91b 100644
--- a/sys/contrib/ipfilter/netinet/ip_rules.c
+++ b/sys/contrib/ipfilter/netinet/ip_rules.c
@@ -12,22 +12,18 @@
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/socket.h>
-#if defined(__FreeBSD_version) && (__FreeBSD_version >= 40000)
+#if defined(__FreeBSD_version)
 # if defined(_KERNEL)
 #  include <sys/libkern.h>
 # else
 #  include <sys/unistd.h>
 # endif
-#endif
-#if defined(__NetBSD_Version__) && (__NetBSD_Version__ >= 399000000)
 #else
-# if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__sgi)
-#  include <sys/systm.h>
-# endif
+# include <sys/systm.h>
 #endif
 #include <sys/errno.h>
 #include <sys/param.h>
-#if !defined(__SVR4) && !defined(__svr4__) && !defined(__hpux)
+#if !defined(__SVR4)
 # include <sys/mbuf.h>
 #endif
 #if defined(__FreeBSD__)