Silence false truncation warning

We know we won't overflow here, because we've manually truncated the
input string already. But gcc can still complain, so we need to shut it
up by ignoring the return value.

vncviewer/DesktopWindow.cxx

@@ -321,8 +321,11 @@ void DesktopWindow::setName(const char *name)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
 
-  snprintf(windowNameStr, sizeof(windowNameStr),
-           labelFormat, truncatedName);
+  if (snprintf(windowNameStr, sizeof(windowNameStr), "%s - TigerVNC",
+               truncatedName) >= (int)sizeof(windowNameStr)) {
+    // This is just to shut up the compiler, as we've already made sure
+    // we won't truncate anything
+  }
 
 #pragma GCC diagnostic pop