implement `Buildings::completebuild` function export from DF

to be used by `build-now`

docs/changelog.txt

@@ -130,11 +130,12 @@ Template for new versions:
 - unavailable tools are no longer listed in the tag indices in the online docs
 
 ## API
+- added ``Buildings::completebuild``, used to link a newly created building into the world
 - added ``Items::getCapacity``, returns the capacity of an item as a container (reverse-engineered), needed for `combine`
 
 ## Lua
 - added ``GRAY`` color aliases for ``GREY`` colors
-- added ``dfhack.items.getCapacity`` to expose the new module API
+- added ``dfhack.items.completebuild`` and ``dfhack.items.getCapacity`` to expose new module APIs
 - ``utils.search_text``: text search routine (generalized from internal ``widgets.FilteredList`` logic)
 
 ## Removed

library/LuaApi.cpp

@@ -2440,6 +2440,7 @@ static const LuaWrapper::FunctionReg dfhack_buildings_module[] = {
     WRAPM(Buildings, isPenPasture),
     WRAPM(Buildings, isPitPond),
     WRAPM(Buildings, isActive),
+    WRAPM(Buildings, completebuild),
     { NULL, NULL }
 };
 

library/include/modules/Buildings.h

@@ -289,5 +289,10 @@ DFHACK_EXPORT df::building* findPenPitAt(df::coord coord);
  * Returns the units currently in the given cage
  */
 DFHACK_EXPORT bool getCageOccupants(df::building_cagest *cage, std::vector<df::unit*> &units);
+
+/**
+ * Finalizes a new building into the world
+ */
+DFHACK_EXPORT void completebuild(df::building* bld, char in_play);
 }
 }

library/modules/Buildings.cpp

@@ -1707,3 +1707,15 @@ bool Buildings::getCageOccupants(df::building_cagest *cage, vector<df::unit*> &u
 
     return true;
 }
+
+void Buildings::completebuild(df::building* bld, char in_play)
+{
+    CHECK_NULL_POINTER(bld);
+
+    auto fp = df::global::buildingst_completebuild;
+    CHECK_NULL_POINTER(fp);
+
+    typedef std::function<void(df::building* bld, char)> FT;
+    auto f = reinterpret_cast<FT*>(fp);
+    (*f)(bld, in_play);
+}