yersinia: fixed build by helping to find the right pcap headers

security/yersinia/yersinia.conf

@@ -2,7 +2,7 @@
 # This copyright note is auto-generated by ./scripts/Create-CopyPatch.
 #
 # Filename: package/.../yersinia/yersinia.conf
-# Copyright (C) 2007 The OpenSDE Project
+# Copyright (C) 2007 - 2010 The OpenSDE Project
 #
 # More information can be found in the files COPYING and README.
 #
@@ -12,6 +12,9 @@
 # GNU General Public License can be found in the file COPYING.
 # --- SDE-COPYRIGHT-NOTE-END ---
 
+# libpcap is needed
+pkgprefix -t libpcap
+var_append extraconfopt ' ' "--with-pcap-includes=$( pkgprefix -r includedir libpcap )"
 
 if ! pkginstalled gtk+ ; then
 	var_append confopt ' ' "--disable-gtk"