diff -ruN ipchains-1.3.6-org/ipfwc_kernel_headers.h ipchains-1.3.6/ipfwc_kernel_headers.h
--- ipchains-1.3.6-org/ipfwc_kernel_headers.h	Tue May 19 05:17:16 1998
+++ ipchains-1.3.6/ipfwc_kernel_headers.h	Sun Sep 20 21:05:37 1998
@@ -3,6 +3,8 @@
 #ifndef _FWCHAINS_KERNEL_HEADERS_H
 #define _FWCHAINS_KERNEL_HEADERS_H
 
+#include <features.h>
+
 #if defined(__GLIBC__) && __GLIBC__ == 2
 #include <netinet/ip.h>
 #include <netinet/ip_icmp.h>
@@ -11,11 +13,15 @@
 #include <net/if.h>
 #include <sys/types.h>
 
+#if defined(__GLIBC_MINOR__) && __GLIBC_MINOR__ == 1
+/* currently there's nothing to include */
+#else
 typedef u_int64_t __u64;
 typedef u_int32_t __u32;
 typedef int32_t __s32;
 typedef u_int16_t __u16;
 typedef u_int8_t __u8;
+#endif
 
 #else /* libc5 */
 #include <sys/socket.h>