Fix integer overflow in xmlBufferDump()

* tree.c:
(xmlBufferDump):
- Cap the return value to INT_MAX.

tree.c

@@ -7413,7 +7413,7 @@ xmlBufferGrow(xmlBufferPtr buf, unsigned int len) {
  */
 int
 xmlBufferDump(FILE *file, xmlBufferPtr buf) {
-    int ret;
+    size_t ret;
 
     if (buf == NULL) {
 #ifdef DEBUG_BUFFER
@@ -7432,7 +7432,7 @@ xmlBufferDump(FILE *file, xmlBufferPtr buf) {
     if (file == NULL)
 	file = stdout;
     ret = fwrite(buf->content, sizeof(xmlChar), buf->use, file);
-    return(ret);
+    return(ret > INT_MAX ? INT_MAX : (int)ret);
 }
 
 /**