-/* Provide some sort of boolean type. We use stdbool.h if it's
- available. This must be after all inclusion of system headers,
- as some of them will mess us up. */
-#undef bool
-#undef true
-#undef false
+/* Redefine abort to report an internal error w/o coredump, and
+ reporting the location of the error in the source file. */
+extern void fancy_abort (const char *, int, const char *) ATTRIBUTE_NORETURN;
+#define abort() fancy_abort (__FILE__, __LINE__, __FUNCTION__)
+
+/* Use gcc_assert(EXPR) to test invariants. */
+#if ENABLE_ASSERT_CHECKING
+#define gcc_assert(EXPR) \
+ ((void)(!(EXPR) ? fancy_abort (__FILE__, __LINE__, __FUNCTION__), 0 : 0))
+#else
+/* Include EXPR, so that unused variable warnings do not occur. */
+#define gcc_assert(EXPR) ((void)(0 && (EXPR)))
+#endif
+
+/* Use gcc_unreachable() to mark unreachable locations (like an
+ unreachable default case of a switch. Do not use gcc_assert(0). */
+#define gcc_unreachable() (fancy_abort (__FILE__, __LINE__, __FUNCTION__))
+
+/* Provide a fake boolean type. We make no attempt to use the
+ C99 _Bool, as it may not be available in the bootstrap compiler,
+ and even if it is, it is liable to be buggy.
+ This must be after all inclusion of system headers, as some of
+ them will mess us up. */
+