--- mctr2/mctr/ttcn3_start.orig	2024-11-14 11:50:43 UTC
+++ mctr2/mctr/ttcn3_start
@@ -18,11 +18,15 @@ fi
 # hide next line from expect \
 fi
 
+# Set the default TTCN3_DIR only if TTCN3_DIR is unset. \
+: ${TTCN3_DIR=%%TTCN3_DIR%%}; \
+case ${TTCN3_DIR} in \
+"") SETENV= ;; \
+*)  SETENV="env TTCN3_DIR=${TTCN3_DIR}" ;; \
+esac
 
-
-
 # the next line restarts using expect \
-exec expect "$0" "$@"
+exec ${SETENV} expect "$0" "$@"
 
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