+/* Define macros for some gcc attributes. This permits us to use the
+ macros freely, and know that they will come into play for the
+ version of gcc in which they are supported. */
+
+#if (GCC_VERSION < 2007)
+# define __attribute__(x)
+#endif
+
+/* Attribute __malloc__ on functions was valid as of gcc 2.96. */
+#ifndef ATTRIBUTE_MALLOC
+# if (GCC_VERSION >= 2096)
+# define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
+# else
+# define ATTRIBUTE_MALLOC
+# endif /* GNUC >= 2.96 */
+#endif /* ATTRIBUTE_MALLOC */
+
+/* Attributes on labels were valid as of gcc 2.93 and g++ 4.5. For
+ g++ an attribute on a label must be followed by a semicolon. */
+#ifndef ATTRIBUTE_UNUSED_LABEL
+# ifndef __cplusplus
+# if GCC_VERSION >= 2093
+# define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED
+# else
+# define ATTRIBUTE_UNUSED_LABEL
+# endif
+# else
+# if GCC_VERSION >= 4005
+# define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED ;
+# else
+# define ATTRIBUTE_UNUSED_LABEL
+# endif
+# endif
+#endif
+
+#ifndef ATTRIBUTE_UNUSED
+#define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
+#endif /* ATTRIBUTE_UNUSED */
+
+/* Before GCC 3.4, the C++ frontend couldn't parse attributes placed after the
+ identifier name. */
+#if ! defined(__cplusplus) || (GCC_VERSION >= 3004)
+# define ARG_UNUSED(NAME) NAME ATTRIBUTE_UNUSED
+#else /* !__cplusplus || GNUC >= 3.4 */
+# define ARG_UNUSED(NAME) NAME
+#endif /* !__cplusplus || GNUC >= 3.4 */
+
+#ifndef ATTRIBUTE_NORETURN
+#define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+#endif /* ATTRIBUTE_NORETURN */
+
+/* Attribute `nonnull' was valid as of gcc 3.3. */
+#ifndef ATTRIBUTE_NONNULL
+# if (GCC_VERSION >= 3003)
+# define ATTRIBUTE_NONNULL(m) __attribute__ ((__nonnull__ (m)))
+# else
+# define ATTRIBUTE_NONNULL(m)
+# endif /* GNUC >= 3.3 */
+#endif /* ATTRIBUTE_NONNULL */
+
+/* Attribute `pure' was valid as of gcc 3.0. */
+#ifndef ATTRIBUTE_PURE
+# if (GCC_VERSION >= 3000)
+# define ATTRIBUTE_PURE __attribute__ ((__pure__))
+# else
+# define ATTRIBUTE_PURE
+# endif /* GNUC >= 3.0 */
+#endif /* ATTRIBUTE_PURE */
+
+/* Use ATTRIBUTE_PRINTF when the format specifier must not be NULL.
+ This was the case for the `printf' format attribute by itself
+ before GCC 3.3, but as of 3.3 we need to add the `nonnull'
+ attribute to retain this behavior. */
+#ifndef ATTRIBUTE_PRINTF
+#define ATTRIBUTE_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n))) ATTRIBUTE_NONNULL(m)
+#define ATTRIBUTE_PRINTF_1 ATTRIBUTE_PRINTF(1, 2)
+#define ATTRIBUTE_PRINTF_2 ATTRIBUTE_PRINTF(2, 3)
+#define ATTRIBUTE_PRINTF_3 ATTRIBUTE_PRINTF(3, 4)
+#define ATTRIBUTE_PRINTF_4 ATTRIBUTE_PRINTF(4, 5)
+#define ATTRIBUTE_PRINTF_5 ATTRIBUTE_PRINTF(5, 6)
+#endif /* ATTRIBUTE_PRINTF */
+
+/* Use ATTRIBUTE_FPTR_PRINTF when the format attribute is to be set on
+ a function pointer. Format attributes were allowed on function
+ pointers as of gcc 3.1. */
+#ifndef ATTRIBUTE_FPTR_PRINTF
+# if (GCC_VERSION >= 3001)
+# define ATTRIBUTE_FPTR_PRINTF(m, n) ATTRIBUTE_PRINTF(m, n)
+# else
+# define ATTRIBUTE_FPTR_PRINTF(m, n)
+# endif /* GNUC >= 3.1 */
+# define ATTRIBUTE_FPTR_PRINTF_1 ATTRIBUTE_FPTR_PRINTF(1, 2)
+# define ATTRIBUTE_FPTR_PRINTF_2 ATTRIBUTE_FPTR_PRINTF(2, 3)
+# define ATTRIBUTE_FPTR_PRINTF_3 ATTRIBUTE_FPTR_PRINTF(3, 4)
+# define ATTRIBUTE_FPTR_PRINTF_4 ATTRIBUTE_FPTR_PRINTF(4, 5)
+# define ATTRIBUTE_FPTR_PRINTF_5 ATTRIBUTE_FPTR_PRINTF(5, 6)
+#endif /* ATTRIBUTE_FPTR_PRINTF */
+
+/* Use ATTRIBUTE_NULL_PRINTF when the format specifier may be NULL. A
+ NULL format specifier was allowed as of gcc 3.3. */
+#ifndef ATTRIBUTE_NULL_PRINTF
+# if (GCC_VERSION >= 3003)
+# define ATTRIBUTE_NULL_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n)))
+# else
+# define ATTRIBUTE_NULL_PRINTF(m, n)
+# endif /* GNUC >= 3.3 */
+# define ATTRIBUTE_NULL_PRINTF_1 ATTRIBUTE_NULL_PRINTF(1, 2)
+# define ATTRIBUTE_NULL_PRINTF_2 ATTRIBUTE_NULL_PRINTF(2, 3)
+# define ATTRIBUTE_NULL_PRINTF_3 ATTRIBUTE_NULL_PRINTF(3, 4)
+# define ATTRIBUTE_NULL_PRINTF_4 ATTRIBUTE_NULL_PRINTF(4, 5)
+# define ATTRIBUTE_NULL_PRINTF_5 ATTRIBUTE_NULL_PRINTF(5, 6)
+#endif /* ATTRIBUTE_NULL_PRINTF */
+
+/* Attribute `sentinel' was valid as of gcc 3.5. */
+#ifndef ATTRIBUTE_SENTINEL
+# if (GCC_VERSION >= 3005)
+# define ATTRIBUTE_SENTINEL __attribute__ ((__sentinel__))
+# else
+# define ATTRIBUTE_SENTINEL
+# endif /* GNUC >= 3.5 */
+#endif /* ATTRIBUTE_SENTINEL */
+
+
+#ifndef ATTRIBUTE_ALIGNED_ALIGNOF
+# if (GCC_VERSION >= 3000)
+# define ATTRIBUTE_ALIGNED_ALIGNOF(m) __attribute__ ((__aligned__ (__alignof__ (m))))
+# else
+# define ATTRIBUTE_ALIGNED_ALIGNOF(m)
+# endif /* GNUC >= 3.0 */
+#endif /* ATTRIBUTE_ALIGNED_ALIGNOF */
+
+/* Useful for structures whose layout must much some binary specification
+ regardless of the alignment and padding qualities of the compiler. */
+#ifndef ATTRIBUTE_PACKED
+# define ATTRIBUTE_PACKED __attribute__ ((packed))
+#endif
+
+/* Attribute `hot' and `cold' was valid as of gcc 4.3. */
+#ifndef ATTRIBUTE_COLD
+# if (GCC_VERSION >= 4003)
+# define ATTRIBUTE_COLD __attribute__ ((__cold__))
+# else
+# define ATTRIBUTE_COLD
+# endif /* GNUC >= 4.3 */
+#endif /* ATTRIBUTE_COLD */
+#ifndef ATTRIBUTE_HOT
+# if (GCC_VERSION >= 4003)
+# define ATTRIBUTE_HOT __attribute__ ((__hot__))
+# else
+# define ATTRIBUTE_HOT
+# endif /* GNUC >= 4.3 */
+#endif /* ATTRIBUTE_HOT */
+
+/* We use __extension__ in some places to suppress -pedantic warnings
+ about GCC extensions. This feature didn't work properly before
+ gcc 2.8. */
+#if GCC_VERSION < 2008
+#define __extension__
+#endif
+
+/* This is used to declare a const variable which should be visible
+ outside of the current compilation unit. Use it as
+ EXPORTED_CONST int i = 1;
+ This is because the semantics of const are different in C and C++.
+ "extern const" is permitted in C but it looks strange, and gcc
+ warns about it when -Wc++-compat is not used. */
+#ifdef __cplusplus
+#define EXPORTED_CONST extern const
+#else
+#define EXPORTED_CONST const
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+