Fix downloading of packages file when fetching pkg:// deps

Previous code was downloading it a for each dep that used pkg://.

erlang.mk

@@ -120,7 +120,7 @@ define get_dep
 ifeq (,$(findstring pkg://,$(word 1,$(dep_$(1)))))
 	git clone -n -- $(word 1,$(dep_$(1))) $(DEPS_DIR)/$(1)
 else
-	$(if $(wildcard $(PKG_FILE)),,$(call get_pkg_file))
+	if [ ! -f $(PKG_FILE) ]; then $(call get_pkg_file); fi
 	git clone -n -- `awk 'BEGIN { FS = "\t" }; \
 		$$$$1 == "$(subst pkg://,,$(word 1,$(dep_$(1))))" { print $$$$2 }' \
 		$(PKG_FILE)` $(DEPS_DIR)/$(1)