[libpng16] Increased warning buffer in pngerror.c from 128 to 192.

pngerror.c

@@ -283,11 +283,13 @@ void
 png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p,
    png_const_charp message)
 {
-   /* The internal buffer is just 128 bytes - enough for all our messages,
-    * overflow doesn't happen because this code checks!
+   /* The internal buffer is just 192 bytes - enough for all our messages,
+    * overflow doesn't happen because this code checks!  If someone figures
+    * out how to send us a message longer than 192 bytes, all that will
+    * happen is that the message will be truncated appropriately.
     */
    size_t i = 0; /* Index in the msg[] buffer: */
-   char msg[128];
+   char msg[192];
 
    /* Each iteration through the following loop writes at most one character
     * to msg[i++] then returns here to validate that there is still space for