Add new call includeExternal()

Works like include(), but any containers created by the included scripts (projects, solutions, rules) will be marked as external.

src/base/api.lua

@@ -46,7 +46,9 @@
 		end
 
 		_G[containerName] = function(name)
-			return api._setContainer(class, name)
+			local c = api._setContainer(class, name)
+			c.external = api._isIncludingExternal
+			return c
 		end
 
 		_G["external" .. containerName:capitalized()] = function(name)
@@ -60,6 +62,20 @@
 
 
 
+---
+-- Register a general-purpose includeExternal() call which works just like
+-- include(), but marks any containers created while evaluating the included
+-- scripts as external.
+---
+
+	function includeExternal(fname)
+		api._isIncludingExternal = true
+		include(fname)
+		api._isIncludingExternal = nil
+	end
+
+
+
 ---
 -- Return the global configuration container. You could just call global()
 -- too, but this is much faster.