-/* Attributes are only in recent versions of GCC */
-#if defined(__GNUC__) && (__GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 4))
-# define _XBT_GNUC_PRINTF( format_idx, arg_idx ) \
- __attribute__((__format__ (__printf__, format_idx, arg_idx)))
-# define _XBT_GNUC_SCANF( format_idx, arg_idx ) \
- __attribute__((__format__ (__scanf__, format_idx, arg_idx)))
-# define _XBT_GNUC_NORETURN __attribute__((__noreturn__))
-# define _XBT_GNUC_UNUSED __attribute__((__unused__))
-/* Constructor priorities exist since gcc 4.3. Apparently, they are however not
- * supported on Macs. */
-# if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) && !defined(__APPLE__)
-# define _XBT_GNUC_CONSTRUCTOR(prio) __attribute__((__constructor__ (prio)))
-# define _XBT_GNUC_DESTRUCTOR(prio) __attribute__((__destructor__ (prio)))
-# else
-# define _XBT_GNUC_CONSTRUCTOR(prio) __attribute__((__constructor__))
-# define _XBT_GNUC_DESTRUCTOR(prio) __attribute__((__destructor__))
-# endif
-# undef _XBT_NEED_INIT_PRAGMA
-
-#else /* !__GNUC__ */
-# define _XBT_GNUC_PRINTF( format_idx, arg_idx )
-# define _XBT_GNUC_SCANF( format_idx, arg_idx )
-# define _XBT_GNUC_NORETURN
-# define _XBT_GNUC_UNUSED
-# define _XBT_GNUC_CONSTRUCTOR(prio)
-# define _XBT_GNUC_DESTRUCTOR(prio)
-# define _XBT_NEED_INIT_PRAGMA 1
-
-#endif /* !__GNUC__ */
+// Teach the compiler that some code path is unreacheable:
+#if defined(__has_builtin)
+# if __has_builtin(__builtin_unreachable)
+# define XBT_UNREACHABLE() __builtin_unreachable()
+# else
+# include <stdlib.h>
+# define XBT_UNREACHABLE() abort()
+# endif
+#elif (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
+# define XBT_UNREACHABLE() __builtin_unreachable()
+#else
+# include <stdlib.h>
+# define XBT_UNREACHABLE() abort()
+#endif