IPA_Emulation: Make dependencies to RSL/MGCP/SCCP/GSUP conditional

Let's use the preprocessor to avoid IPA_Emulation pulling *all*
dependencies into each and any of our projects.  The code readability
suffers a bit from the many #ifdefs, but compilation speed increases
if we don't have to pull in all those (recursive) dependencies.

After all, a BTS test case will never need SCCP, GSUP or MGCP.

Change-Id: Ic0231adbd2171214de133d26b3fbf36130ee8aa0
diff --git a/sgsn/regen_makefile.sh b/sgsn/regen_makefile.sh
index 0691164..a85f79c 100755
--- a/sgsn/regen_makefile.sh
+++ b/sgsn/regen_makefile.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 
-FILES="*.ttcn BSSGP_EncDec.cc LLC_EncDec.cc IPL4asp_PT.cc IPL4asp_discovery.cc TCCConversion.cc TCCInterface.cc NS_CodecPort_CtrlFunctDef.cc RLCMAC_EncDec.cc Native_FunctionDefs.cc SDP_EncDec.cc SDP_parse_.tab.c lex.SDP_parse_.c TELNETasp_PT.cc IPA_CodecPort_CtrlFunctDef.cc GTPU_EncDec.cc GTPC_EncDec.cc GTP_CodecPort_CtrlFunctDef.cc"
+FILES="*.ttcn *.ttcnpp BSSGP_EncDec.cc LLC_EncDec.cc IPL4asp_PT.cc IPL4asp_discovery.cc TCCConversion.cc TCCInterface.cc NS_CodecPort_CtrlFunctDef.cc RLCMAC_EncDec.cc Native_FunctionDefs.cc TELNETasp_PT.cc IPA_CodecPort_CtrlFunctDef.cc GTPU_EncDec.cc GTPC_EncDec.cc GTP_CodecPort_CtrlFunctDef.cc"
+
+export CPPFLAGS_TTCN3="-DIPA_EMULATION_GSUP"
 
 ../regen-makefile.sh SGSN_Tests.ttcn $FILES