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/msc/regen_makefile.sh b/msc/regen_makefile.sh
index dacd10b..84b16f7 100755
--- a/msc/regen_makefile.sh
+++ b/msc/regen_makefile.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 
-FILES="*.ttcn SCCP_EncDec.cc  SCTPasp_PT.cc  TCCConversion.cc TCCInterface.cc UD_PT.cc MNCC_EncDec.cc IPL4asp_PT.cc IPL4asp_discovery.cc SDP_EncDec.cc RTP_EncDec.cc IPA_CodecPort_CtrlFunctDef.cc RTP_CodecPort_CtrlFunctDef.cc MGCP_CodecPort_CtrlFunctDef.cc TELNETasp_PT.cc Native_FunctionDefs.cc *.c"
+FILES="*.ttcn *.ttcnpp SCCP_EncDec.cc  SCTPasp_PT.cc  TCCConversion.cc TCCInterface.cc UD_PT.cc MNCC_EncDec.cc IPL4asp_PT.cc IPL4asp_discovery.cc SDP_EncDec.cc RTP_EncDec.cc IPA_CodecPort_CtrlFunctDef.cc RTP_CodecPort_CtrlFunctDef.cc MGCP_CodecPort_CtrlFunctDef.cc TELNETasp_PT.cc Native_FunctionDefs.cc *.c"
+
+export CPPFLAGS_TTCN3="-DIPA_EMULATION_MGCP -DIPA_EMULATION_GSUP"
 
 ../regen-makefile.sh MSC_Tests.ttcn $FILES