gistfile1.txt

/*
 * With XPG4, you must define _XOPEN_SOURCE_EXTENDED, it is redundant (or
 * conflicting) when _XOPEN_SOURCE is 500 or greater.  If NCURSES_WIDECHAR is
 * not already defined, e.g., if the platform relies upon nonstandard feature
 * test macros, define it at this point if the standard feature test macros
 * indicate that it should be defined.
 */
#ifndef NCURSES_WIDECHAR
#if defined(_XOPEN_SOURCE_EXTENDED) || (defined(_XOPEN_SOURCE) && (_XOPEN_SOURCE - 0 >= 500))
#define NCURSES_WIDECHAR 1
#else
#define NCURSES_WIDECHAR 0
#endif
#endif /* NCURSES_WIDECHAR */