fix windows build

Author: Tyrael

ext/standard/basic_functions.c

@@ -4151,13 +4151,6 @@ PHP_FUNCTION(putenv)
 	&& _putenv(pe.putenv_string) == 0
 # endif
 	) { /* success */
-#  if _MSC_VER < 1500
-	/* Yet another VC6 bug, unset may return env not found */
-	if (error_code != 0 ||
-		(error_code == 0 && GetLastError() == ERROR_ENVVAR_NOT_FOUND)) {
-#  else
-	if (error_code != 0) { /* success */
-#  endif
 # endif
 #endif
 		zend_hash_add(&BG(putenv_ht), pe.key, pe.key_len + 1, (void **) &pe, sizeof(putenv_entry), NULL);