+#define APT_GCC_VERSION 0
+#endif
+
+/* likely() and unlikely() can be used to mark boolean expressions
+ as (not) likely true which will help the compiler to optimise */
+#if APT_GCC_VERSION >= 0x0300
+ #define likely(x) __builtin_expect (!!(x), 1)
+ #define unlikely(x) __builtin_expect (!!(x), 0)
+#else
+ #define likely(x) (x)
+ #define unlikely(x) (x)
+#endif
+
+#if APT_GCC_VERSION >= 0x0300
+ #define APT_DEPRECATED __attribute__ ((deprecated))
+ #define APT_DEPRECATED_MSG(X) __attribute__ ((deprecated(X)))
+ #define APT_CONST __attribute__((const))
+ #define APT_PURE __attribute__((pure))
+ #define APT_NORETURN __attribute__((noreturn))
+ #define APT_PRINTF(n) __attribute__((format(printf, n, n + 1)))
+ #define APT_WEAK __attribute__((weak));
+#else
+ #define APT_DEPRECATED
+ #define APT_DEPRECATED_MSG
+ #define APT_CONST
+ #define APT_PURE
+ #define APT_NORETURN
+ #define APT_PRINTF(n)
+ #define APT_WEAK
+#endif
+
+#if APT_GCC_VERSION > 0x0302
+ #define APT_NONNULL(...) __attribute__((nonnull(__VA_ARGS__)))
+ #define APT_MUSTCHECK __attribute__((warn_unused_result))
+#else
+ #define APT_NONNULL(...)
+ #define APT_MUSTCHECK
+#endif
+
+#if APT_GCC_VERSION >= 0x0400
+ #define APT_SENTINEL __attribute__((sentinel))
+ #define APT_PUBLIC __attribute__ ((visibility ("default")))
+ #define APT_HIDDEN __attribute__ ((visibility ("hidden")))
+#else
+ #define APT_SENTINEL
+ #define APT_PUBLIC
+ #define APT_HIDDEN