client: add unified function to generate MGCP messages

currently the only way to generate MGCP messages is to use
mgcp_msg_crcx(), mgcp_msg_mdcx() and mgcp_msg_dlcx(). All
three function take a fixed set of parameters via their
parameter list. There is no way to add or leave away optional
parameters.

add function mgcp_msg_gen(), this function takes a unified
message struct. The struct features a presence bitmask which
allows to enable and disable parameters as needed. It is also
possible to add new parameters in the future without breaking
the API.

Depends: libosmocore I15e1af68616309555d0ed9ac5da027c9833d42e3

Change-Id: I29c5e2fb972896faeb771ba040f015592487fcbe
diff --git a/tests/mgcp_client/mgcp_client_test.ok b/tests/mgcp_client/mgcp_client_test.ok
index d35f2d6..e3b6113 100644
--- a/tests/mgcp_client/mgcp_client_test.ok
+++ b/tests/mgcp_client/mgcp_client_test.ok
@@ -28,4 +28,34 @@
   head.trans_id = 1
   head.comment = OK
   audio_port = 16002
+
+Generated CRCX message:
+CRCX 1 23@mgw MGCP 1.0

+C: 2f

+I: 11

+L: p:20, a:AMR, nt:IN

+M: sendrecv

+
+Generated MDCX message:
+MDCX 2 23@mgw MGCP 1.0

+C: 2f

+I: 11

+M: sendrecv

+

+c=IN IP4 192.168.100.23

+m=audio 1234 RTP/AVP 255

+
+Generated DLCX message:
+DLCX 3 23@mgw MGCP 1.0

+C: 2f

+I: 11

+
+Generated AUEP message:
+AUEP 4 23@mgw MGCP 1.0

+
+Generated RSIP message:
+RSIP 5 23@mgw MGCP 1.0

+
+Overfolow test:
+
 Done