add 'libosmotrau' for TRAU/RTP related code
This new library is intended to include everything related to
interfacing actual voice channels either via E1 or via RTP.
The first module in the library is osmo_rtp, based on the ortp library.
diff --git a/libosmotrau.pc.in b/libosmotrau.pc.in
new file mode 100644
index 0000000..d15c5fa
--- /dev/null
+++ b/libosmotrau.pc.in
@@ -0,0 +1,10 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: Osmocom TRAU (E1/RTP) Library
+Description: C Utility Library
+Version: @VERSION@
+Libs: -L${libdir} -losmotrau
+Cflags: -I${includedir}/