src: Adding pkgconfig script, so apps can use pkg-config to get all necesasry parameters to compile against the library

Change-Id: Ie19fc258c2602a3f0685c247e328e9d3166639dc
diff --git a/configure.ac b/configure.ac
index 695e7db..6647cdc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -161,5 +161,6 @@
                  examples/Makefile
                  tools/Makefile
                  tests/Makefile
-                 tests_boost/Makefile])
+                 tests_boost/Makefile
+                 libndn-cpp-dev.pc])
 AC_OUTPUT