diff --git a/common/Makefile b/common/Makefile
index 98c9d36..6cc6143 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -31,9 +31,11 @@
 DEFAULT_ENVIRONMENT_PATH = "defaultenv"
 endif
 
+ifneq ($(CONFIG_DEFAULT_ENVIRONMENT_PATH),"")
 DEFAULT_ENVIRONMENT_PATH += $(CONFIG_DEFAULT_ENVIRONMENT_PATH)
+endif
 
-ENV_FILES := $(shell cd $(srctree); for i in $(DEFAULT_ENVIRONMENT_PATH); do find $${i} -type f -exec readlink -f {} \;; done)
+ENV_FILES := $(shell cd $(srctree); for i in $(DEFAULT_ENVIRONMENT_PATH); do find $${i} -type f -exec readlink -f '{}' \;; done)
 
 endif # ifdef CONFIG_DEFAULT_ENVIRONMENT