include libgen.h in application.cc for the declaration of basename.

Unfortunately it defines basename as a macro, so also change member
function name from basename() to get_basename().

base/application.h

@@ -41,7 +41,7 @@ namespace base {
 
 	private:
 		void usage();
-		std::string basename(std::string const &path) const;
+		std::string get_basename(std::string const &path) const;
 
 		std::list<command const *> cmds_;
 	};