Support building steam engines on top of brooks without any down stairs.

library/include/TileTypes.h

@@ -203,6 +203,12 @@ namespace DFHack
         return ENUM_ATTR(tiletype_shape, passable_flow, tileShape(tiletype));
     }
 
+    inline
+    bool FlowPassableDown(df::tiletype tiletype)
+    {
+        return ENUM_ATTR(tiletype_shape, passable_flow_down, tileShape(tiletype));
+    }
+
     inline
     bool isWalkable(df::tiletype tiletype)
     {

library/xml

@@ -1 +1 @@
-Subproject commit 02e0e0d7b9a7ef708a621ef5511a24bf8657b4a2
+Subproject commit 4b2124957e282683480eaf05922e63c353364ec1

plugins/steam-engine.cpp

@@ -320,7 +320,7 @@ struct workshop_hook : df::building_workshopst {
             for (int y = y1; y <= y2; y++)
             {
                 auto ptile = Maps::getTileType(x,y,z);
-                if (!ptile || !LowPassable(*ptile))
+                if (!ptile || !FlowPassableDown(*ptile))
                     continue;
 
                 auto pltile = Maps::getTileType(x,y,z-1);
@@ -891,7 +891,7 @@ IMPLEMENT_VMETHOD_INTERPOSE(dwarfmode_hook, feed);
  * Scan raws for matching workshop buildings.
  */
 
-static bool find_engines()
+static bool find_engines(color_ostream &out)
 {
     engines.clear();
 
@@ -943,6 +943,8 @@ static bool find_engines()
 
         if (!ws.gear_tiles.empty())
             engines.push_back(ws);
+        else
+            out.printerr("%s has no gear tiles - ignoring.\n", wslist[i]->code.c_str());
     }
 
     return !engines.empty();
@@ -973,7 +975,7 @@ DFhackCExport command_result plugin_onstatechange(color_ostream &out, state_chan
 {
     switch (event) {
     case SC_WORLD_LOADED:
-        if (find_engines())
+        if (find_engines(out))
         {
             out.print("Detected steam engine workshops - enabling plugin.\n");
             enable_hooks(true);