diff --git a/build.sh b/build.sh
index 4ce8b01..c284189 100755
--- a/build.sh
+++ b/build.sh
@@ -118,7 +118,7 @@ build() {
 		DEFAULT_BUILD_CPUS=1 DEFAULT_BUILD_LAST_FAILED_PKG_FNAME="" DEFAULT_BUILD_LOG_FNAME=""			\
 		DEFAULT_BUILD_STEPS="" DEFAULT_BUILD_VARS="" DEFAULT_CLEAR_PREFIX_PATHS="" DEFAULT_GIT_ARGS=""		\
 		DEFAULT_GITROOT_HEAD="" DEFAULT_LOG_ENV_VARS=""	DEFAULT_TARGET="" DEFAULT_WGET_ARGS=""			\
-		MIDIPIX_BUILD_PWD=""; DEFAULT_BUILD_STATUS_IN_PROGRESS_FNAME="";
+		MIDIPIX_BUILD_PWD=""; DEFAULT_BUILD_STATUS_IN_PROGRESS_FNAME=""; EX_PKG_DISPATCH_WAIT="";
 	if ! . "${0%/*}/subr/build_init.subr"; then
 		_rc=1; printf "Error: failed to source \`${0%/*}/subr/build_init.subr'." >&2;
 	elif ! build_init "${@}"; then