Patch to solve memory protect violation and clear __error_numberafter call CC_lookup_characterset

Hello,

I have detected fatal memory error protection on call strdup 
connectio.c(1045) and wrong setting conn.__error_number on CC_lookup_lo 
when "select oid, typbasetype from pg_type where typname = 'lo'" doesn't 
return any record.

I used this patch to solve the problem on debian stretch with 
odbc-postgresql:amd64 version 1:09.05.0400-2.

--- psqlodbc-09.05.0400.orig/connection.c
+++ psqlodbc-09.05.0400/connection.c
@@ -1041,12 +1041,13 @@ CC_connect(ConnectionClass *self, char *
   if (retsend)
       retsend = CC_send_settings(self, 
GET_NAME(self->connInfo.conn_settings));

-    if (CC_get_errornumber(self) > 0)
+    if ((CC_get_errornumber(self) > 0) && (CC_get_errormsg(self) != NULL))
          saverr = strdup(CC_get_errormsg(self));
      CC_clear_error(self);            /* clear any error */
      CC_lookup_lo(self);            /* a hack to get the oid of
                             our large object oid type */

+    CC_clear_error(self);            /* clear any error */
      /* Multibyte handling */
      CC_lookup_characterset(self);
      if (CC_get_errornumber(self) > 0)

It's probably better to clear self.__error_number directly on 
CC_lookup_lo and when error_number is equal 110.

Thank's for the job.


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