@@ -1,9 +1,9 @@
 #! /bin/bash
 
 TCLVERS="8.4.19"
-if echo "$1" | grep '^[0-9][0-9]*\.' >/dev/null || echo "$1" | grep '^cvs_' >/dev/null; then
+if echo "$1" | grep '^[0-9][0-9]*\.' >/dev/null || echo "$1" | egrep '^(cvs|fossil)_' >/dev/null; then
 	TCLVERS="$1"
 
 	shift
 fi
 export TCLVERS
@@ -103,10 +103,24 @@
 else
 	KITCREATOR_RC="$(echo "$(pwd)/kitsh/buildsrc"/kitsh-*/kit.rc)"
 fi
 export KITCREATOR_ICON KITCREATOR_RC
 
+# Determine how we invoke a Tcl interpreter
+if [ -z "${TCLSH_NATIVE}" ]; then
+	TCLSH_NATIVE="false"
+fi
+for testsh in "${TCLSH_NATIVE}" tclsh tclsh8.4 tclsh8.5 tclsh8.6 "${TCLKIT:-tclkit}"; do
+	if echo 'exit 0' | "${testsh}" >/dev/null 2>/dev/null; then
+		TCLSH_NATIVE="${testsh}"
+
+		break
+	fi
+done
+export TCLSH_NATIVE
+
+# Do build
 failedpkgs=""
 buildfailed="0"
 for pkg in tcl tclvfs zlib ${KITCREATOR_PKGS} kitsh; do
 	echo -n "Building ${pkg} ..."