Revert "chflags: Add a new UF_DONTCACHE flag"

This reverts commit 74654ba3b1.

Apparently it breaks cross building from Linux for some
reason.  I'll admit I didn't even know we supported cross
building from Linux.

lib/libc/gen/strtofflags.c

@@ -80,9 +80,7 @@ static struct {
 	{ "nosparse",		0, UF_SPARSE	},
 	{ "nousparse",		0, UF_SPARSE	},
 	{ "nosystem",		0, UF_SYSTEM	},
-	{ "nousystem",		0, UF_SYSTEM	},
-	{ "nodontcache",	0, UF_DONTCACHE	},
-	{ "noudontcache",	0, UF_DONTCACHE	}
+	{ "nousystem",		0, UF_SYSTEM	}
 };
 #define nmappings	(sizeof(mapping) / sizeof(mapping[0]))
 

sys/fs/tmpfs/tmpfs_subr.c

@@ -2042,7 +2042,7 @@ tmpfs_chflags(struct vnode *vp, u_long flags, struct ucred *cred,
 	if ((flags & ~(SF_APPEND | SF_ARCHIVED | SF_IMMUTABLE | SF_NOUNLINK |
 	    UF_APPEND | UF_ARCHIVE | UF_HIDDEN | UF_IMMUTABLE | UF_NODUMP |
 	    UF_NOUNLINK | UF_OFFLINE | UF_OPAQUE | UF_READONLY | UF_REPARSE |
-	    UF_SPARSE | UF_SYSTEM | UF_DONTCACHE)) != 0)
+	    UF_SPARSE | UF_SYSTEM)) != 0)
 		return (EOPNOTSUPP);
 
 	/* Disallow this operation if the file system is mounted read-only. */

sys/sys/stat.h

@@ -327,7 +327,6 @@ struct nstat {
 #define	UF_REPARSE	0x00000400	/* Windows reparse point file bit */
 #define	UF_ARCHIVE	0x00000800	/* file needs to be archived */
 #define	UF_READONLY	0x00001000	/* Windows readonly file bit */
-#define	UF_DONTCACHE	0x00002000	/* don't cache file data (NFSv4) */
 /* This is the same as the MacOS X definition of UF_HIDDEN. */
 #define	UF_HIDDEN	0x00008000	/* file is hidden */
 

sys/ufs/ufs/ufs_vnops.c

@@ -667,7 +667,7 @@ ufs_setattr(
 		    SF_NOUNLINK | SF_SNAPSHOT | UF_APPEND | UF_ARCHIVE |
 		    UF_HIDDEN | UF_IMMUTABLE | UF_NODUMP | UF_NOUNLINK |
 		    UF_OFFLINE | UF_OPAQUE | UF_READONLY | UF_REPARSE |
-		    UF_SPARSE | UF_SYSTEM | UF_DONTCACHE)) != 0)
+		    UF_SPARSE | UF_SYSTEM)) != 0)
 			return (EOPNOTSUPP);
 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
 			return (EROFS);