create libosmoisdn sub-library
There are some parts of libosmogsm which are not really GSM specific,
but rather ISDN bits that were inherited by GSM. This includes the
I.460 multiplex as well as the core LAPD protocol.
Let's move those bits to its own libosmoisdn library, before we add
more ISDN specific bits to the wrong place.
Backwards-compatibility is created by making libosmogsm depend on
libosmoisdn, and by providing wrapper include files for source
compatibility.
Change-Id: Ib1a6c762322fd5047be3188b1df22408ef06aa50
diff --git a/libosmoisdn.pc.in b/libosmoisdn.pc.in
new file mode 100644
index 0000000..fedbb69
--- /dev/null
+++ b/libosmoisdn.pc.in
@@ -0,0 +1,11 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: Osmocom ISDN Library
+Description: ISDN Library
+Version: @VERSION@
+Requires: talloc, libosmocore
+Libs: -L${libdir} -losmoisdn
+Cflags: -I${includedir}/