#if defined(DUK_F_C99) || defined(DUK_F_CPP11)
/* C99 / C++11 and above: rely on va_copy() which is required. */
#define DUK_VA_COPY(dest,src) va_copy(dest,src)
#else
/* Clang: assume we have __va_copy() in non-C99 mode. */
#define DUK_VA_COPY(dest,src) __va_copy(dest,src)
#endif

#define DUK_NORETURN(decl)  decl __attribute__((noreturn))

#if defined(__clang__) && defined(__has_builtin)
#if __has_builtin(__builtin_unreachable)
#define DUK_UNREACHABLE()  do { __builtin_unreachable(); } while (0)
#endif
#endif

#define DUK_USE_BRANCH_HINTS
#define DUK_LIKELY(x)    __builtin_expect((x), 1)
#define DUK_UNLIKELY(x)  __builtin_expect((x), 0)
#if defined(__clang__) && defined(__has_builtin)
#if __has_builtin(__builtin_unpredictable)
#define DUK_UNPREDICTABLE(x)  __builtin_unpredictable((x))
#endif
#endif

#if defined(DUK_F_C99) || defined(DUK_F_CPP11)
#define DUK_NOINLINE        __attribute__((noinline))
#define DUK_INLINE          inline
#define DUK_ALWAYS_INLINE   inline __attribute__((always_inline))
#endif

/* DUK_HOT */
/* DUK_COLD */

#if defined(DUK_F_DLL_BUILD) && defined(DUK_F_WINDOWS)
#snippet "msvc_visibility.h.in"
#else
#snippet "gcc_clang_visibility.h.in"
#endif

#if defined(DUK_F_CPP)
#define DUK_USE_COMPILER_STRING "clang"
#else
#define DUK_USE_COMPILER_STRING "clang"
#endif

#undef DUK_USE_VARIADIC_MACROS
#if defined(DUK_F_C99) || defined(DUK_F_CPP11)
#define DUK_USE_VARIADIC_MACROS
#endif

#define DUK_USE_UNION_INITIALIZERS

#undef DUK_USE_FLEX_C99
#undef DUK_USE_FLEX_ZEROSIZE
#undef DUK_USE_FLEX_ONESIZE
#if defined(DUK_F_C99)
#define DUK_USE_FLEX_C99
#else
#define DUK_USE_FLEX_ZEROSIZE
#endif

#undef DUK_USE_GCC_PRAGMAS
#define DUK_USE_PACK_CLANG_ATTR

#if defined(__clang__) && defined(__has_builtin)
#if __has_builtin(__builtin_bswap64)
#define DUK_BSWAP64(x) ((duk_uint64_t) __builtin_bswap64((duk_uint64_t) (x)))
#endif
#if __has_builtin(__builtin_bswap32)
#define DUK_BSWAP32(x) ((duk_uint32_t) __builtin_bswap32((duk_uint32_t) (x)))
#endif
#if __has_builtin(__builtin_bswap16)
#define DUK_BSWAP16(x) ((duk_uint16_t) __builtin_bswap16((duk_uint16_t) (x)))
#endif
#endif