add libpcap

svn path=/nixpkgs/trunk/; revision=4211

pkgs/development/libraries/libpcap/default.nix

@@ -0,0 +1,10 @@
+{stdenv, fetchurl, flex, bison}:
+
+stdenv.mkDerivation {
+  name = "libpcap-0.9.4";
+  src = fetchurl {
+      url = http://www.tcpdump.org/release/libpcap-0.9.4.tar.gz;
+      md5 = "79025766e8027df154cb1f32de8a7974";
+  };
+  buildInputs = [flex bison];
+}