MT#55283 unify __attribute__() test macros

Change-Id: Ia2ef8e995c78a2dd1fe33e37f78eed6e58191ac7

lib/auxlib.h

@@ -448,7 +448,7 @@ INLINE pid_t gettid(void) {
 
 /*** TAINT FUNCTIONS ***/
 
-#if __has_attribute(__error__)
+#if HAS_ATTR(__error__)
 /* This is not supported in clang, and on gcc it might become inert if the
  * symbol gets remapped to a builtin or stack protected function, but it
  * otherwise gives better diagnostics. */

lib/compat.h

@@ -7,12 +7,16 @@
 # define INLINE static inline __attribute__((always_inline))
 #endif
 
-#define ACCESS(...)
 #if defined __has_attribute
-# if __has_attribute(access)
-#  undef ACCESS
-#  define ACCESS(...) __attribute__((access(__VA_ARGS__)))
-# endif
+# define HAS_ATTR(x) __has_attribute(x)
+#else
+# define HAS_ATTR(x) 0
+#endif
+
+#if HAS_ATTR(access)
+# define ACCESS(...) __attribute__((access(__VA_ARGS__)))
+#else
+# define ACCESS(...)
 #endif