generalize shared code from regen_makefile.sh into shared helper script

Change-Id: I86a738420851a7d9e3bdb2671f6862c3d505a4ba
diff --git a/bsc-nat/regen_makefile.sh b/bsc-nat/regen_makefile.sh
index 6d0ac12..a3c6243 100755
--- a/bsc-nat/regen_makefile.sh
+++ b/bsc-nat/regen_makefile.sh
@@ -4,12 +4,4 @@
 
 FILES="*.ttcn SCCP_EncDec.cc IPA_CodecPort_CtrlFunctDef.cc IPL4asp_PT.cc IPL4asp_discovery.cc TCCConversion.cc TCCInterface.cc RTP_EncDec.cc SDP_EncDec.cc *.c MGCP_CodecPort_CtrlFunctDef.cc"
 
-ttcn3_makefilegen -l -f $MAIN $FILES
-sed -i -e 's/# TTCN3_DIR = /TTCN3_DIR = \/usr/' Makefile
-sed -i -e 's/LDFLAGS = /LDFLAGS = -L \/usr\/lib\/titan /' Makefile
-#sed -i -e 's/TTCN3_LIB = ttcn3-parallel/TTCN3_LIB = ttcn3/' Makefile
-sed -i -e 's/CPPFLAGS = -D$(PLATFORM) -I$(TTCN3_DIR)\/include/CPPFLAGS = -D$(PLATFORM) -I$(TTCN3_DIR)\/include -I\/usr\/include\/titan/' Makefile
-
-# for TITAN 6.3.0
-sed -i -e 's/TTCN3_DIR = $/TTCN3_DIR = \/usr/' Makefile
-sed -i -e 's/\/bin\/compiler/\/bin\/ttcn3_compiler/' Makefile
+../regen-makefile.sh $MAIN $FILES