pkgconfig: link upnp, nat-pmp

Change-Id: I6b373a24e1ca9db3ad4684627d1c27b5a9ace706
diff --git a/dhtnet.pc.in b/dhtnet.pc.in
index 9ea2f2f..00a628e 100644
--- a/dhtnet.pc.in
+++ b/dhtnet.pc.in
@@ -6,6 +6,7 @@
 Description: C++ peer to peer networking library
 Version: @VERSION@
 Libs: -L${libdir} -ldhtnet
+Libs.private: @libsprivate@
 Requires: opendht >= 2.6
-Requires.private: libpjproject
+Requires.private: libpjproject @requiresprivate@
 Cflags: -I${includedir}