Use shell variable, instead of makefile var.
Change-Id: I802b145b563145437135412473704f911c8c1474
diff --git a/core/Makefile b/core/Makefile
index 35773bf..6947624 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -589,7 +589,7 @@
# $(5): size of the partition
define build-userimage-ext-target
@mkdir -p $(dir $(2))
- $(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$(PATH) \
+ $(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH \
$(MKEXTUSERIMG) $(INTERNAL_USERIMAGES_SPARSE_EXT_FLAG) $(1) $(2) $(4) $(3) $(5)
endef
else