Use printf instead of echo in Makefile help target

Author: daxxog

Diff for: Makefile

@@ -1,6 +1,6 @@
 .PHONY: help
 help:
-	@echo "available targets -->\n"
+	@printf "available targets -->\n\n"
 	@cat Makefile | grep ".PHONY" | grep -v ".PHONY: _" | sed 's/.PHONY: //g'