Possible 9.0 bug

I have a small test case (shown below) that is not working under
9.0beta1 but works fine under 8.1. I have other code that is virtually
identical to this that does not encounter the error.

When I connect using empty string user id and password (and specifying
ident in pg_hba) I get the following:

================
>testconnect

Database connection failed: connection failed:-402:could not connect to
database "mchs" on line 53

Could not connect to database: connection failed:-402:could not connect
to database "mchs" on line 53

=================

When I put in non-empty user id and password, it is OK:

>testconnect

Connected to database OK

Disconnected from database

=================

This is my test case:

=================

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define USERNAME ""
#define PASSWORD ""

#include <sqlca.h>

int db_connect(char *);
void db_disconnect();

int main(int argc, char *argv[])
{
char message[81];

if (db_connect(message) != 0) {
printf("Could not connect to database: %s\n", message);
} else {
printf("Connected to database OK\n");
db_disconnect();
}

return 0;
}

int db_connect(char *message)
{
int result = 0;

EXEC SQL BEGIN DECLARE SECTION;
VARCHAR username[128];
VARCHAR password[32];
EXEC SQL END DECLARE SECTION;

strcpy(username.arr,USERNAME);
username.len = strlen(username.arr);

strcpy(password.arr,PASSWORD);
password.len = strlen(password.arr);

EXEC SQL CONNECT TO mchs USER :username IDENTIFIED BY :password;
if (sqlca.sqlcode == 0) {
result = 0;
} else {
result = 1;
sprintf(message,"connection failed:%d:%s\n",
sqlca.sqlcode, sqlca.sqlerrm.sqlerrmc);
printf("\nDatabase connection failed: %s\n", message);
}
return result;
}

void db_disconnect()
{
EXEC SQL ROLLBACK;

EXEC SQL CONNECT RESET;

printf("\nDisconnected from database\n");
}