Fix memory leak in os.get_current_directory on failure on *nix systems

core/os/os_darwin.odin

@@ -701,6 +701,7 @@ get_current_directory :: proc() -> string {
 			return string(cwd)
 		}
 		if Errno(get_last_error()) != ERANGE {
+			delete(buf)
 			return ""
 		}
 		resize(&buf, len(buf)+page_size)