Include <linux/vmalloc.h> explicitly on x86

Commit 1f059dfdf5d1 ("mm/vmalloc: Add empty <asm/vmalloc.h> headers
and use them from <linux/vmalloc.h>") restructured kernel header
dependencies since kernel v5.6-rc1, necessitating explicit inclusion
of <linux/vmalloc.h> on x86 architectures.

This explicitly includes <linux/vmalloc.h> on x86, preventing build
errors caused by implicit declarations in kernels since v5.6-rc1.

Co-authored-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Close #1

Author: rota1001

main.c

@@ -9,6 +9,9 @@
 #include <linux/sysfs.h>
 #include <linux/version.h>
 #include <linux/workqueue.h>
+#if defined(CONFIG_X86)
+#include <linux/vmalloc.h>
+#endif
 
 #include "game.h"
 #include "mcts.h"

scripts/aspell-pws

@@ -177,3 +177,4 @@ kfifo
 PTR
 ttt
 tictactoe
+vmalloc