NetHack secret doors patch (rebased against 3.6.2)

diff --git c/include/extern.h w/include/extern.h
index 6959e24..5f7e299 100644
--- c/include/extern.h
+++ w/include/extern.h
@@ -365,6 +365,7 @@ E int FDECL(back_to_glyph, (XCHAR_P, XCHAR_P));
 E int FDECL(zapdir_to_glyph, (int, int, int));
 E int FDECL(glyph_at, (XCHAR_P, XCHAR_P));
 E void NDECL(set_wall_state);
+E int FDECL(set_wall, (int, int, int));
 E void FDECL(unset_seenv, (struct rm *, int, int, int, int));
 E int FDECL(warning_of, (struct monst *));

@@ -2326,6 +2327,7 @@ E void FDECL(fill_room, (struct mkroom *, BOOLEAN_P));
 E boolean FDECL(load_special, (const char *));
 E xchar FDECL(selection_getpoint, (int, int, struct opvar *));
 E struct opvar *FDECL(selection_opvar, (char *));
+E void FDECL(set_door_orientation, (int, int));
 E void FDECL(opvar_free_x, (struct opvar *));
 E void FDECL(set_selection_floodfillchk, (int FDECL((*), (int,int))));
 E void FDECL(selection_floodfill, (struct opvar *, int, int, BOOLEAN_P));
diff --git c/src/display.c w/src/display.c
index c5b155b..e673644 100644
--- c/src/display.c
+++ w/src/display.c
@@ -138,7 +138,6 @@ STATIC_DCL boolean FDECL(more_than_one, (int, int, int, int, int));
 #endif

 STATIC_DCL int FDECL(set_twall, (int, int, int, int, int, int, int, int));
-STATIC_DCL int FDECL(set_wall, (int, int, int));
 STATIC_DCL int FDECL(set_corn, (int, int, int, int, int, int, int, int));
 STATIC_DCL int FDECL(set_crosswall, (int, int));
 STATIC_DCL void FDECL(set_seenv, (struct rm *, int, int, int, int));
@@ -2007,7 +2006,7 @@ int x1, y1, x2, y2, x3, y3;
 }

 /* Return wall mode for a horizontal or vertical wall. */
-STATIC_OVL int
+int
 set_wall(x, y, horiz)
 int x, y, horiz;
 {
diff --git c/src/lock.c w/src/lock.c
index 270ab18..9e29ca9 100644
--- c/src/lock.c
+++ w/src/lock.c
@@ -1049,6 +1049,35 @@ int x, y;
         } else
             res = FALSE;
         break;
+    case WAN_MAKE_INVISIBLE:
+        if (door->doormask & (D_LOCKED | D_CLOSED)) {
+            /* Riders shall not be blocked */
+            if (Is_astralevel(&u.uz))
+              {
+                msg = "The door momentarily fades.";
+                res = FALSE;
+                break;
+              }
+            /* Probably should not count as vandalism,
+             * but the original shop door will still reappear */
+            if (*in_rooms(x, y, SHOPBASE))
+                add_damage(x, y, 0L);
+            /* BUG: secret doors can only pretend to be straight walls,
+             * so a door created with wizard lock in a room corner
+             * or other weird position will display as a wrong kind
+             * of wall when made invisible.  This is not noticeable
+             * with the default symset, but all others will glitch.
+             * There's no easy way to fix it short of arbitrarily refusing
+             * to vanish doors at weird positions, which is also ugly. */
+            door->typ = SDOOR;
+            set_door_orientation(x, y);
+            door->doormask &= ~WM_MASK;
+            door->wall_info |= set_wall(x, y, door->horizontal);
+            newsym(x, y);
+            msg = "The door vanishes!";
+        } else
+            res = FALSE;
+        break;
     default:
         impossible("magic (%d) attempted on door.", otmp->otyp);
         break;
diff --git c/src/sp_lev.c w/src/sp_lev.c
index cd95210..dba499e 100644
--- c/src/sp_lev.c
+++ w/src/sp_lev.c
@@ -52,7 +52,6 @@ STATIC_DCL void FDECL(set_wall_property, (XCHAR_P, XCHAR_P, XCHAR_P, XCHAR_P,
 STATIC_DCL void NDECL(shuffle_alignments);
 STATIC_DCL void NDECL(count_features);
 STATIC_DCL void NDECL(remove_boundary_syms);
-STATIC_DCL void FDECL(set_door_orientation, (int, int));
 STATIC_DCL void FDECL(maybe_add_door, (int, int, struct mkroom *));
 STATIC_DCL void NDECL(link_doors_rooms);
 STATIC_DCL void NDECL(fill_rooms);
@@ -717,7 +716,7 @@ remove_boundary_syms()
 }

 /* used by sel_set_door() and link_doors_rooms() */
-STATIC_OVL void
+void
 set_door_orientation(x, y)
 int x, y;
 {
diff --git c/src/zap.c w/src/zap.c
index a9350eb..ebe80fe 100644
--- c/src/zap.c
+++ w/src/zap.c
@@ -3394,6 +3394,7 @@ struct obj **pobj; /* object tossed/used, set to NULL
             case WAN_OPENING:
             case WAN_LOCKING:
             case WAN_STRIKING:
+            case WAN_MAKE_INVISIBLE:
             case SPE_KNOCK:
             case SPE_WIZARD_LOCK:
             case SPE_FORCE_BOLT:
@@ -3401,7 +3402,8 @@ struct obj **pobj; /* object tossed/used, set to NULL
                     if (cansee(bhitpos.x, bhitpos.y)
                         || (obj->otyp == WAN_STRIKING && !Deaf))
                         learnwand(obj);
-                    if (levl[bhitpos.x][bhitpos.y].doormask == D_BROKEN
+                    if (IS_DOOR(levl[bhitpos.x][bhitpos.y].typ)
+                        && levl[bhitpos.x][bhitpos.y].doormask == D_BROKEN
                         && *in_rooms(bhitpos.x, bhitpos.y, SHOPBASE)) {
                         shopdoor = TRUE;
                         add_damage(bhitpos.x, bhitpos.y, SHOP_DOOR_COST);