unixodbc vs iodbc

Index: src/pyodbcmodule.cpp
--- src/pyodbcmodule.cpp.orig
+++ src/pyodbcmodule.cpp
@@ -307,7 +307,13 @@ static bool AllocateEnv()
     if (PyObject_TypeCheck(odbcversion, &PyUnicode_Type)) {
         if (PyUnicode_CompareWithASCIIString(odbcversion, "3.8") == 0)
         {
+#if 0
             defaultVersion = (SQLPOINTER)SQL_OV_ODBC3_80;
+#else
+            Py_DECREF(odbcversion);
+            PyErr_SetString(PyExc_RuntimeError, "using iODBC - odbcversion cannot be set to 3.8.");
+            return false;
+#endif
         }
     }
     Py_DECREF(odbcversion);
@@ -1074,7 +1080,9 @@ static const ConstantDef aConstants[] = {
     MAKECONST(SQL_CONVERT_DECIMAL),
     MAKECONST(SQL_CONVERT_DOUBLE),
     MAKECONST(SQL_CONVERT_FLOAT),
+#ifdef SQL_CONVERT_GUID
     MAKECONST(SQL_CONVERT_GUID),
+#endif
     MAKECONST(SQL_CONVERT_INTEGER),
     MAKECONST(SQL_CONVERT_INTERVAL_DAY_TIME),
     MAKECONST(SQL_CONVERT_INTERVAL_YEAR_MONTH),