include missing header for snprintf definition

Upstream-Status: Submitted [https://bugs.webkit.org/show_bug.cgi?id=197088]
Signed-off-by: Khem Raj <raj.khem@gmail.com>

--- a/Source/WebCore/platform/text/TextCodec.cpp
+++ b/Source/WebCore/platform/text/TextCodec.cpp
@@ -28,6 +28,7 @@
 #include "TextCodec.h"
 
 #include <array>
+#include <cstdio>
 
 namespace WebCore {