Blessed potion of polymorph asks user for monster to poly into

... unless there's some other form that would override the choice,
such as a worn dragon armor, lycanthropy, or vampirism.

The polymorph will be in effect for 10-24 turns.

include/hack.h

@@ -81,6 +81,15 @@ enum dismount_types {
     DISMOUNT_BYCHOICE = 6
 };
 
+/* polyself flags */
+enum polyself_flags {
+    POLY_NOFLAGS    = 0x00,
+    POLY_CONTROLLED = 0x01,
+    POLY_MONSTER    = 0x02,
+    POLY_REVERT     = 0x04,
+    POLY_LOW_CTRL   = 0x08
+};
+
 /* sellobj_state() states */
 #define SELL_NORMAL (0)
 #define SELL_DELIBERATE (1)