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/Makefile.am b/Makefile.am
index 5f69d3b..60188c1 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -134,3 +134,6 @@
 libndn_cpp_dev_la_CFLAGS  = @OPENSSL_INCLUDES@ @CRYPTOPP_INCLUDES@ @SQLITE3_CFLAGS@     @BOOST_CPPFLAGS@
 
 dist_noinst_SCRIPTS = autogen.sh
+
+pkgconfigdir = $(libdir)/pkgconfig
+pkgconfig_DATA = libndn-cpp-dev.pc