pkgconfig: link library

Change-Id: Ie1987ef0c2794af0f094627b701643cb5f1c2421
diff --git a/dhtnet.pc.in b/dhtnet.pc.in
index efe9236..9ea2f2f 100644
--- a/dhtnet.pc.in
+++ b/dhtnet.pc.in
@@ -5,6 +5,7 @@
 Name: dhtnet
 Description: C++ peer to peer networking library
 Version: @VERSION@
+Libs: -L${libdir} -ldhtnet
 Requires: opendht >= 2.6
 Requires.private: libpjproject
 Cflags: -I${includedir}