check for JTE support within the tested xorriso build

releng/releng_build_isojigdo

@@ -76,6 +76,11 @@ RES="${IMG}.iso ${IMG}.new ${IMG}.md5 ${IMG}.jigdo ${IMG}.template"
 main() {
 # version details, incl. underlying libraries
 "${XOR}" -version
+if ! "${XOR}" -version | grep libjte >/dev/null 2>&1; then
+ printf "\n$0: JTE not supported with this xorriso build. Install jigit and rebuild."
+ printf "\n$0: See http://www.einval.com/~steve/software/JTE/\n"
+ exit 51
+fi
 
 # remove cruft from previous runs
 # rm -f ${RES}