add DUK_API_ENTRY_STACK

src/duk_hthread.h

@@ -20,6 +20,10 @@
                                                  * always added to user-defined 'extra' for e.g. the
                                                  * duk_check_stack() call.
                                                  */
+#define DUK_VALSTACK_API_ENTRY_MINIMUM  DUK_API_ENTRY_STACK
+                                                /* number of elements guaranteed to be user accessible
+                                                 * (in addition to call arguments) on Duktape/C function entry.
+                                                 */
 #define DUK_VALSTACK_DEFAULT_MAX        1000000
 
 #define DUK_CALLSTACK_GROW_STEP         8       /* roughly 256 bytes */

src/duktape.h

@@ -122,6 +122,11 @@ struct duk_memory_functions {
  */
 #define DUK_VARARGS                       (-1)
 
+/* Number of value stack entries (in addition to actual call arguments)
+ * guaranteed to be allocated on entry to a Duktape/C function.
+ */
+#define DUK_API_ENTRY_STACK               64
+
 /* Value types, used by e.g. duk_get_type() */
 #define DUK_TYPE_NONE                     0    /* no value, e.g. invalid index */
 #define DUK_TYPE_UNDEFINED                1    /* Ecmascript undefined */