diff --git a/lib/zig.h b/lib/zig.h
index c2b68f0fe5..f7bf1ec118 100644
--- a/lib/zig.h
+++ b/lib/zig.h
@@ -1789,12 +1789,13 @@ typedef zig_i128 zig_f128;
 #define zig_cast_f16 (zig_f16)
 #define zig_cast_f32 (zig_f32)
 #define zig_cast_f64 (zig_f64)
-#define zig_cast_f80 (zig_f80)
 #define zig_cast_c_longdouble (zig_c_longdouble)
 
 #if _MSC_VER && !zig_has_f128
+#define zig_cast_f80
 #define zig_cast_f128
 #else
+#define zig_cast_f80 (zig_f80)
 #define zig_cast_f128 (zig_f128)
 #endif