Fix strict aliasing warning in rb_int128_to_numeric

If we don't have uint128, then rb_int128_to_numeric emits a strict
aliasing warning:

    numeric.c:3641:39: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
    3641 |         return rb_uint128_to_numeric(*(rb_uint128_t*)&n);
         |                                       ^~~~~~~~~~~~~~~~~

1 files changed, 4 insertions, 1 deletions

diff --git a/numeric.c b/numeric.c
index d9e837644f..1942a6164f 100644
--- a/numeric.c
+++ b/numeric.c
@@ -3638,7 +3638,10 @@ rb_int128_to_numeric(rb_int128_t n)
     }
     else {
         // Positive value
-        return rb_uint128_to_numeric(*(rb_uint128_t*)&n);
+        union uint128_int128_conversion conversion = {
+            .int128 = n
+        };
+        return rb_uint128_to_numeric(conversion.uint128);
     }
 #endif
 }