diff --git a/Makefile b/Makefile
index 1d539c6c4..b1154f873 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 .PHONY: gen dev-reset all clean test web website
 
-.SHELLFLAGS += -x -e
+.SHELLFLAGS += ${SHELLFLAGS} -e
 PWD = $(shell pwd)
 UID = $(shell id -u)
 GID = $(shell id -g)