9553 C11 functions quick_exit and at_quick_exit should be visible in C++11.

*** 56,68 ****
  #endif  /* __STDC_VERSION__ - 0 >= 201112L */
  #endif  /* !defined(_NORETURN_KYWD) */
  
  #if !defined(_STRICT_SYMBOLS) || defined(_STDC_C11)
  extern void *aligned_alloc(size_t, size_t);
  extern int at_quick_exit(void (*)(void));
  extern _NORETURN_KYWD void quick_exit(int);
! #endif /* !_STRICT_SYMBOLS || _STDC_C11 */
  
  #if __cplusplus >= 199711L
  }
  #endif
  
--- 56,71 ----
  #endif  /* __STDC_VERSION__ - 0 >= 201112L */
  #endif  /* !defined(_NORETURN_KYWD) */
  
  #if !defined(_STRICT_SYMBOLS) || defined(_STDC_C11)
  extern void *aligned_alloc(size_t, size_t);
+ #endif /* !_STRICT_SYMBOLS || _STDC_C11 */
+ 
+ #if !defined(_STRICT_SYMBOLS) || defined(_STDC_C11) || __cplusplus >= 201103L
  extern int at_quick_exit(void (*)(void));
  extern _NORETURN_KYWD void quick_exit(int);
! #endif /* !_STRICT_SYMBOLS || _STDC_C11 || __cplusplus >= 201103L */
  
  #if __cplusplus >= 199711L
  }
  #endif