die() if variable expansion fails

src/include/build.sh

@@ -130,7 +130,7 @@ expand_variables() {
         done
     echo "s|__CODENAME__|$CODENAME|;"     >> "$script"
     echo "s|__VERSION__|$(get_version)|;" >> "$script"
-    perl -wp "$script"
+    perl -wp "$script" || die "expand_variables failed"
     rm "$script"
 }