Make ipv6 support optional. Patch by Steffen Schulz <sf@cbg.dyndns.org>

Submitted upstream as http://bugzilla.netfilter.org/show_bug.cgi?id=588
diff -ru iptables-1.4.2/configure.ac iptables-1.4.2_patched/configure.ac
--- iptables-1.4.2/configure.ac	2009-03-29 15:49:24.764299587 +0000
+++ iptables-1.4.2_patched/configure.ac	2009-03-29 15:38:29.082512186 +0000
@@ -37,6 +37,9 @@
 	[enable_devel="$enableval"], [enable_devel="yes"])
 AC_ARG_ENABLE([libipq],
 	AS_HELP_STRING([--enable-libipq], [Build and install libipq]))
+AC_ARG_ENABLE([ipv6],
+    AS_HELP_STRING([--enable-ipv6], [Build and install ip6tables]),
+    [enable_ipv6="$enableval"], [enable_ipv6="yes"])
 AC_ARG_WITH([pkgconfigdir], AS_HELP_STRING([--with-pkgconfigdir=PATH],
 	[Path to the pkgconfig directory [[LIBDIR/pkgconfig]]]),
 	[pkgconfigdir="$withval"], [pkgconfigdir='${libdir}/pkgconfig'])
@@ -53,6 +56,7 @@
 AM_CONDITIONAL([ENABLE_SHARED], [test "$enable_shared" = "yes"])
 AM_CONDITIONAL([ENABLE_DEVEL], [test "$enable_devel" = "yes"])
 AM_CONDITIONAL([ENABLE_LIBIPQ], [test "$enable_libipq" = "yes"])
+AM_CONDITIONAL([ENABLE_IPV6], [test "$enable_ipv6" == "yes"])
 
 regular_CFLAGS="-D_LARGEFILE_SOURCE=1 -D_LARGE_FILES -D_FILE_OFFSET_BITS=64 \
 	-D_REENTRANT -Wall -Waggregate-return -Wmissing-declarations \
Only in iptables-1.4.2: configure.ac.orig
Only in iptables-1.4.2: configure.ac.rej
diff -ru iptables-1.4.2/Makefile.am iptables-1.4.2_patched/Makefile.am
--- iptables-1.4.2/Makefile.am	2008-10-08 16:31:58.000000000 +0000
+++ iptables-1.4.2_patched/Makefile.am	2009-03-29 15:38:29.082512186 +0000
@@ -80,11 +80,17 @@
 endif
 
 if ENABLE_STATIC
-sbin_PROGRAMS += iptables-static ip6tables-static
+sbin_PROGRAMS += iptables-static
+if ENABLE_IPV6
+sbin_PROGRAMS += ip6tables-static
+endif
+
 endif
 if ENABLE_SHARED
-sbin_PROGRAMS += iptables iptables-multi iptables-restore iptables-save \
-                 ip6tables ip6tables-multi ip6tables-restore ip6tables-save
+sbin_PROGRAMS += iptables iptables-multi iptables-restore iptables-save
+if ENABLE_IPV6
+sbin_PROGRAMS += ip6tables ip6tables-multi ip6tables-restore ip6tables-save
+endif
 endif
 
 iptables.8: ${srcdir}/iptables.8.in extensions/matches4.man extensions/targets4.man
diff -ru iptables-1.4.2/xtables.c iptables-1.4.2_patched/xtables.c
--- iptables-1.4.2/xtables.c	2008-10-08 16:31:58.000000000 +0000
+++ iptables-1.4.2_patched/xtables.c	2009-03-29 15:38:29.082512186 +0000
@@ -964,6 +964,8 @@
 	}
 }
 
+#ifdef ENABLE_IPV6
+
 const char *ip6addr_to_numeric(const struct in6_addr *addrp)
 {
 	/* 0000:0000:0000:0000:0000:000.000.000.000
@@ -1189,6 +1191,7 @@
 			}
 	}
 }
+#endif
 
 void save_string(const char *value)
 {