BSSGP_Emulation: Make L3 (SM/GMM) decoding a compile-time option

This allows us to build low-level tests that don't require all of L3.

Change-Id: I7ef7e93e2cd1d37e7e4a62947ca8dfde30d93b95
diff --git a/sgsn/regen_makefile.sh b/sgsn/regen_makefile.sh
index a239a3b..1d1411e 100755
--- a/sgsn/regen_makefile.sh
+++ b/sgsn/regen_makefile.sh
@@ -2,7 +2,7 @@
 
 FILES="*.ttcn *.ttcnpp *.asn 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 SCCP_EncDec.cc  SCTPasp_PT.cc RANAP_EncDec.cc "
 
-export CPPFLAGS_TTCN3="-DIPA_EMULATION_GSUP -DIPA_EMULATION_CTRL -DUSE_MTP3_DISTRIBUTOR -DRAN_EMULATION_RANAP"
+export CPPFLAGS_TTCN3="-DIPA_EMULATION_GSUP -DIPA_EMULATION_CTRL -DUSE_MTP3_DISTRIBUTOR -DRAN_EMULATION_RANAP -DBSSGP_EM_L3"
 
 ../regen-makefile.sh SGSN_Tests.ttcn $FILES