(svn r16502) -Fix [FS#2935]: when an AI was suspended while in a function called (indirectly) via call/acall/pcall OpenTTD crashed. Fix this by disallowing AIs to be suspended while called via call/acall/pcall.

IMPORTANT FOR AI WRITERS: AIs can no longer call any DoCommand functions (change anything, build vehicles, etc.) in a function called (indirectly) via call/acall/pcall. Where possible, please rewrite your code so it doesn't use call/acall/pcall

src/script/squirrel.hpp

@@ -213,6 +213,11 @@ public:
 	 * Reset the crashed status.
 	 */
 	void ResetCrashed();
+
+	/**
+	 * Are we allowed to suspend the squirrel script at this moment?
+	 */
+	bool CanSuspend();
 };
 
 #endif /* SQUIRREL_HPP */