ipset: changed to use prefix= to install runtime binaries into /{sbin,lib}

network/ipset/ipset.conf

@@ -12,6 +12,9 @@
 # GNU General Public License can be found in the file COPYING.
 # --- SDE-COPYRIGHT-NOTE-END ---
 
+prefix=
+set_confopt
+
 # do not check for kernel sources because we use the ipset modules provided
 # by the linux package
 var_append extraconfopt ' ' "--with-kmod=no"