linux/fs.h: move member alignment check next to definition of struct filename

Instead of doing this compile-time check in some slightly arbitrary user
of struct filename, put it next to the definition.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Rasmus Villemoes <[e-mail]>
Cc: Alexander Viro <[e-mail]>
Cc: Kees Cook <[e-mail]>
Cc: Luc Van Oostenryck <[e-mail]>
Cc: Masahiro Yamada <[e-mail]>
Cc: Nick Desaulniers <[e-mail]>
Cc: Alexey Dobriyan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/namei.c

···
 #include <linux/bitops.h>
 #include <linux/init_task.h>
 #include <linux/uaccess.h>
-#include <linux/build_bug.h>
 
 #include "internal.h"
 #include "mount.h"
···
 	struct filename *result;
 	char *kname;
 	int len;
-	BUILD_BUG_ON(offsetof(struct filename, iname) % sizeof(long) != 0);
 
 	result = audit_reusename(filename);
 	if (result)

include/linux/fs.h

···
 #include <linux/uuid.h>
 #include <linux/errseq.h>
 #include <linux/ioprio.h>
+#include <linux/build_bug.h>
+#include <linux/stddef.h>
 
 #include <asm/byteorder.h>
 #include <uapi/linux/fs.h>
···
 	struct audit_names	*aname;
 	const char		iname[];
 };
+static_assert(offsetof(struct filename, iname) % sizeof(long) == 0);
 
 extern long vfs_truncate(const struct path *, loff_t);
 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,