Different logic for defining CHECK(); 16-bit MSC specific define.

Objects/floatobject.c

@@ -39,11 +39,17 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #undef HUGE_VAL
 #endif
 
-#ifdef HUGE_VAL
+#if defined(_MSC_VER) && _MSC_VER < 850
+#define CHECK(x) /* errno is always set VC++ Ver 1.5*/
+#endif
+
+#if defined(HUGE_VAL) && !defined(CHECK)
 #define CHECK(x) if (errno != 0) ; \
 	else if (-HUGE_VAL <= (x) && (x) <= HUGE_VAL) ; \
 	else errno = ERANGE
-#else
+#endif
+
+#ifndef CHECK
 #define CHECK(x) /* Don't know how to check */
 #endif