libtiff: Fix using __attribute__ libtiff with clang-for-windows (eb36c)

SDL Commits
1 
From eb36ce944f4e836d9e7562848a6bf3c0b1189c92 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 2c27dbdd..558f4365 100644
--- a/libtiff/tiffio.h
+++ b/libtiff/tiffio.h
@@ -261,7 +261,7 @@ 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*/