Fix build of curses with pdcurses. Closes GH-23.
Fix build of curses with pdcurses. Closes GH-23.

Previous refactoring broke extension compilation. This commit
fix that.

shirosaki/rubyinstaller,vemmaverve/rubyinstaller,Rugbyman21/rubyinstaller,Rugbyman21/rubyinstaller,haonaturel/rubyinstaller,auyaauya/rubyinstaller,leonhooijer/rubyinstaller,jaym/rubyinstaller,vemmaverve/rubyinstaller,auyaauya/rubyinstaller,zorosteven/rubyinstaller,shirosaki/rubyinstaller,suvarnaraju/rubyinstaller,haonaturel/rubyinstaller,suvarnaraju/rubyinstaller,auyaauya/rubyinstaller,modulexcite/rubyinstaller,shirosaki/rubyinstaller,jahanzaibbahadur/rubyinstaller,modulexcite/rubyinstaller,jahanzaibbahadur/rubyinstaller,oneclick/rubyinstaller,dreamauya/rubyinstaller,jahanzaibbahadur/rubyinstaller,oneclick/rubyinstaller,modulexcite/rubyinstaller,oneclick/rubyinstaller,jaym/rubyinstaller,dreamauya/rubyinstaller,haonaturel/rubyinstaller,leonhooijer/rubyinstaller,zorosteven/rubyinstaller,vemmaverve/rubyinstaller,dreamauya/rubyinstaller,suvarnaraju/rubyinstaller,jaym/rubyinstaller,Rugbyman21/rubyinstaller,leonhooijer/rubyinstaller,zorosteven/rubyinstaller