libtiff: Fix using __attribute__ libtiff with clang-for-windows (a20b0)

From a20b0b77d0017fdb534aca08785d3d7dab0ef499 Mon Sep 17 00:00:00 2001
From: Yuriy Chernyshov <[EMAIL REDACTED]>
Date: Tue, 5 Sep 2023 09:44:52 +0000
Subject: [PATCH] Fix using __attribute__ libtiff with clang-for-windows

---
 libtiff/tiffio.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libtiff/tiffio.h b/libtiff/tiffio.h
index d6bf0cc5..20460542 100644
--- a/libtiff/tiffio.h
+++ b/libtiff/tiffio.h
@@ -277,7 +277,7 @@ typedef struct
 #define LOGLUV_PUBLIC 1
 #endif
 
-#if defined(__GNUC__) || defined(__attribute__)
+#if defined(__GNUC__) || defined(__clang__) || defined(__attribute__)
 #define TIFF_ATTRIBUTE(x) __attribute__(x)
 #else
 #define TIFF_ATTRIBUTE(x) /*nothing*/