The `mxmlSetOpaquef` and `mxmlSetTextf` functions did not work (Issue #244)

Use _mxml_vstrdupf function, not _mxml_strdupf.

CHANGES.md

@@ -11,6 +11,7 @@
 - The `mxmlSetCDATA`, `mxmlSetElement`, `mxmlSetOpaque`, `mxmlSetOpaquef`,
   `mxmlSetText`, and `mxmlSetTextf` functions caused a use-after-free bug if
   the value came from the same node (Issue #241)
+- The `mxmlSetOpaquef` and `mxmlSetTextf` functions did not work (Issue #244)
 
 
 # Changes in Mini-XML 2.12

mxml-set.c

@@ -243,7 +243,7 @@ mxmlSetOpaquef(mxml_node_t *node,	/* I - Node to set */
   */
 
   va_start(ap, format);
-  s = _mxml_strdupf(format, ap);
+  s = _mxml_vstrdupf(format, ap);
   va_end(ap);
 
   if (node->value.opaque)
@@ -360,7 +360,7 @@ mxmlSetTextf(mxml_node_t *node,		/* I - Node to set */
   */
 
   va_start(ap, format);
-  s = _mxml_strdupf(format, ap);
+  s = _mxml_vstrdupf(format, ap);
   va_end(ap);
 
   if (node->value.text.string)