libtiff: TIFFUnlinkDirectory(): reset tif_dirnumber

SDL Commits
1 
From e146a61d9d4f55164de2e416584b1138d1a38b88 Mon Sep 17 00:00:00 2001
From: Even Rouault <[EMAIL REDACTED]>
Date: Fri, 6 Jan 2023 15:17:58 +0100
Subject: [PATCH] TIFFUnlinkDirectory(): reset tif_dirnumber

---
 libtiff/tif_dir.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libtiff/tif_dir.c b/libtiff/tif_dir.c
index 804ed6f9..396fbd93 100644
--- a/libtiff/tif_dir.c
+++ b/libtiff/tif_dir.c
@@ -2232,6 +2232,7 @@ int TIFFUnlinkDirectory(TIFF *tif, tdir_t dirn)
     tif->tif_row = (uint32_t)-1;
     tif->tif_curstrip = (uint32_t)-1;
     tif->tif_curdir = TIFF_NON_EXISTENT_DIR_NUMBER;
+    tif->tif_dirnumber = 0;
     _TIFFCleanupIFDOffsetAndNumberMaps(tif);
     return (1);
 }