Fix an embarassing typo.

This is why we do PRs, even for quick fixes and don't just push to master because we're the project lead and yolo.

etc/kaleidoscope-builder.conf

@@ -63,6 +63,7 @@ get_arduino_pref() {
 dump_arduino_prefs() {
 # SKETCH and -build-path in this command are here because of a bug introduced in Arduino 1.8.10
 # https://github.com/arduino/arduino-builder/issues/341
+
     if [ "x${_ARDUINO_PREFS}x" == "xx" ]; then
 
 	    _ARDUINO_PREFS=$("${ARDUINO_BUILDER}" \
@@ -222,9 +223,9 @@ fi
 : "${ARDUINO_LOCAL_LIB_PATH:=${HOME}/Arduino}"
 : "${ARDUINO_TOOLS_PATH:=${ARDUINO_PATH}/hardware/tools}"
 : "${ARDUINO_PACKAGE_PATH:=${HOME}/.arduino15/packages}"
-
 : "${ARDUINO_BUILDER:=${ARDUINO_PATH}/arduino-builder}"
-: "${ARDUINO_BUILDER_TOOLS_PATH}:=${ARDUINO_PATH}/tools-builder"
+: "${ARDUINO_BUILDER_TOOLS_PATH:=${ARDUINO_PATH}/tools-builder}"
+
 ARDUINO_IDE_VERSION="10607"
 
 ######