add types compatible builtin

This builtin function makes macros gain type safety and also the ability
to statically assert the correctness of typedefs that target external
libraries.

diff --git a/lib/isc/include/isc/util.h b/lib/isc/include/isc/util.h
index 43026a01ef4e2b09961547fc79f0ac5835574b1d..ddfce87c32489cd5fed2826d8eb55aa8544117dd 100644 (file)
--- a/lib/isc/include/isc/util.h
+++ b/lib/isc/include/isc/util.h
@@ -39,6 +39,10 @@
 #define __has_header(x) 0
 #endif
 
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
 /***
  *** General Macros.
  ***/
@@ -303,3 +307,9 @@ mock_assert(const int result, const char *const expression,
                a = b;                    \
                b = __tmp_swap;           \
        }
+
+#if __has_builtin(__builtin_types_compatible_p)
+#define ISC_TYPES_COMPATIBLE(x, y) __builtin_types_compatible_p(x, y)
+#else /* __has_builtin(__builtin_types_compatible_p) */
+#define ISC_TYPES_COMPATIBLE(x, y) 1
+#endif /* __has_builtin(__builtin_types_compatible_p) */