diff --git a/config/vars.mk b/config/vars.mk
index c9d9623..1984ced 100644
--- a/config/vars.mk
+++ b/config/vars.mk
@@ -28,7 +28,7 @@ OS := $(shell uname)
 CUR_DIR := $(shell pwd)
 
 # NDK config
-$(shell err() { echo "$1" && exit 1 })
+$(shell export err() { echo "$1" && exit 1; })
 $(shell [ -d ../android-ndk ] || err "error: ndk not found")
 NDK_DIR := $(shell cd ../android-ndk && pwd && cd -)