add several __has_something macro

With these macros implemented we can write codes just like we can assume
the compiler being clang.  MSC_VERSION_SINCE is defined to implement
those macros, but turned out to be handy for other places.  The -fdeclspec
compiler flag is necessary for clang to properly handle __has_declspec().

1 files changed, 1 insertions, 1 deletions

diff --git a/random.c b/random.c
index 68b47bcf1b..d763a214cd 100644
--- a/random.c
+++ b/random.c
@@ -137,7 +137,7 @@ int_pair_to_real_inclusive(uint32_t a, uint32_t b)
     const uint128_t m = ((uint128_t)1 << dig) | 1;
     uint128_t x = ((uint128_t)a << 32) | b;
     r = (double)(uint64_t)((x * m) >> 64);
-#elif defined HAVE_UINT64_T && !(defined _MSC_VER && _MSC_VER <= 1200)
+#elif defined HAVE_UINT64_T && !MSC_VERSION_BEFORE(1300)
     uint64_t x = ((uint64_t)a << dig_u) +
 	(((uint64_t)b + (a >> dig_u)) >> dig_r64);
     r = (double)x;