Add "only borders" option for If Fields? special node

src/game/boe.specials.cpp

@@ -3407,6 +3407,9 @@ void ifthen_spec(const runtime_state& ctx) {
 				int i = 0;
 				for(short j = spec.ex1b; j < min(spec.ex2b, univ.town->max_dim); j++)
 					for(short k = spec.ex1a; k < min(spec.ex2a, univ.town->max_dim); k++) {
+						// If pict non-zero, exclude rectangle interior
+						if(spec.pic > 0 && i > spec.ex1b && i < spec.ex2b && j > spec.ex1a && j < spec.ex2a)
+							continue;
 						switch(eFieldType(spec.m1)) {
 							// These values are not allowed
 							case SPECIAL_EXPLORED: case SPECIAL_SPOT: case SPECIAL_ROAD:

src/scenario/special-condition.cpp

@@ -74,6 +74,7 @@ namespace {
 		.ex1b(eSpecPicker::NODE);
 	node_properties_t S_FIELDS = node_builder_t(eSpecType::IF_FIELDS)
 		.rect(eLocType::ACTIVE_TOWN)
+		.pict(eSpecPicker::TOGGLE)
 		.msg1(eSpecPicker::FIELD)
 		.msg2(eSpecPicker::NODE);
 	node_properties_t S_PARTY_SIZE = node_builder_t(eSpecType::IF_PARTY_SIZE)