minor refactor, using `WILDCOPY_OVERLENGTH` macro instead of hard-coded 8
diff --git a/Makefile b/Makefile
index 77a67a2..f0d39ea 100644
--- a/Makefile
+++ b/Makefile
@@ -64,6 +64,7 @@
 	@$(MAKE) -C $(ZSTDDIR) $@ > $(VOID)
 	@$(MAKE) -C $(PRGDIR) $@ > $(VOID)
 	@$(MAKE) -C $(ZWRAPDIR) $@ > $(VOID)
+	@rm -f zstd
 	@echo Cleaning completed