Update Modules/mathmodule.c

Author: skirpichev

Modules/mathmodule.c

@@ -2163,7 +2163,7 @@ math_ldexp_impl(PyObject *module, double x, PyObject *i)
     } else {
         errno = 0;
         r = ldexp(x, (int)exp);
-#if _MSC_VER
+#ifdef _MSC_VER
         if (-DBL_MIN < r && r < DBL_MIN) {
             /* Denormal (or zero) results can be incorrectly rounded here (rather,
                truncated).  Fixed in newer versions of the C runtime, included