_XOPEN_SOURCE

[Marco Atzeri]

Dear Corinna,

on  /usr/include/sys/features.h
-------------------------------------------------------
#if !defined(_POSIX_C_SOURCE)  &&  defined(_XOPEN_SOURCE)
  #if _XOPEN_SOURCE == 700      /* POSIX.1-2008 */
    #define _POSIX_C_SOURCE       200809L
   #elif _XOPEN_SOURCE == 600   /* POSIX.1-2001 */
    #define _POSIX_C_SOURCE       200112L
  #endif
#endif
-------------------------------------------------------

the test expect that _XOPEN_SOURCE, when defined, has some
values.

However it seems that it could also be defined and empty:
http://docs.sun.com/app/docs/doc/816-5175/6mbba7f3p?a=view

in this case the compilation will fail with :
/usr/include/sys/features.h:189:21: error: operator '==' has no left operand
/usr/include/sys/features.h:191:24: error: operator '==' has no left operand



Regards
Marco