Fix `write_entire_file`

core/os.odin

@@ -50,7 +50,7 @@ write_entire_file :: proc(name: string, data: []byte, truncate := true) -> (succ
 	defer close(fd);
 
 	bytes_written, write_err := write(fd, data);
-	return write_err != 0;
+	return write_err == 0;
 }
 
 write_ptr :: proc(fd: Handle, data: rawptr, len: int) -> (int, Errno) {