Add '#if !defined(NO_EDITOR)' guards around editorinput/render/logic

These functions aren't needed in a NO_EDITOR build, so it's useful to
reduce the binary size this way.

desktop_version/src/editor.h

@@ -259,11 +259,13 @@ void fillbox(int x, int y, int x2, int y2, int c);
 
 void fillboxabs(int x, int y, int x2, int y2, int c);
 
+#if !defined(NO_EDITOR)
 void editorrender();
 
 void editorlogic();
 
 void editorinput();
+#endif
 
 extern editorclass ed;