L1CTL: Add message segmentation helper via getMsgLen()

As L1CTL is using a stream socket, we need to give the UNIX_DOMAIN
port some clue as to where our L1CTL message boundaries are in the
stream.

This requires a patched UNIX_DOMAIN_SOCKETasp test port with the
following commit applied:

commit 655cb4ab2ac006b3a73d1b679c83081d9743410a
Author: Harald Welte <laforge@gnumonks.org>
Date:   Sun Feb 25 23:25:46 2018 +0100

    Add "getMsgLen" function similar to IPL4asp_PT

Change-Id: Iab33f57cb4311180e521a76307a552d16287b062
diff --git a/lapdm/gen_links.sh b/lapdm/gen_links.sh
index 93655f0..5ecc45c 100755
--- a/lapdm/gen_links.sh
+++ b/lapdm/gen_links.sh
@@ -15,8 +15,11 @@
 FILES="UD_PT.cc  UD_PT.hh  UD_PortType.ttcn  UD_Types.ttcn"
 gen_links $DIR $FILES
 
+DIR=$BASEDIR/titan.TestPorts.Common_Components.Socket-API/src
+FILES="Socket_API_Definitions.ttcn"
+gen_links $DIR $FILES
 
 
 DIR=../library
-FILES="General_Types.ttcn GSM_Types.ttcn GSM_RR_Types.ttcn RLCMAC_CSN1_Types.ttcn Osmocom_Types.ttcn L1CTL_PortType.ttcn L1CTL_Types.ttcn LAPDm_RAW_PT.ttcn LAPDm_Types.ttcn RLCMAC_Types.ttcn RLCMAC_EncDec.cc"
+FILES="General_Types.ttcn GSM_Types.ttcn GSM_RR_Types.ttcn RLCMAC_CSN1_Types.ttcn Osmocom_Types.ttcn L1CTL_PortType.ttcn L1CTL_PortType_CtrlFunct.ttcn L1CTL_PortType_CtrlFunctDef.cc L1CTL_Types.ttcn LAPDm_RAW_PT.ttcn LAPDm_Types.ttcn RLCMAC_Types.ttcn RLCMAC_EncDec.cc"
 gen_links $DIR $FILES