SELECT sip_RECno, 
    user1 = MAX(CASE WHEN ONAY_ID = 1 THEN ONAY END),
    user2 = MAX(CASE WHEN ONAY_ID = 2 THEN ONAY END),
    user3 = MAX(CASE WHEN ONAY_ID = 3 THEN ONAY END),
    user4 = MAX(CASE WHEN ONAY_ID = 4 THEN ONAY END)
FROM dbo.tablename
WHERE sup_RECno = 1
GROUP BY sip_RECno;

EDIT for new data type revelation...

SELECT sip_RECno, 
    user1 = MAX(CASE WHEN ONAY_ID = 1 THEN CONVERT(TINYINT, ONAY) END),
    user2 = MAX(CASE WHEN ONAY_ID = 2 THEN CONVERT(TINYINT, ONAY) END),
    user3 = MAX(CASE WHEN ONAY_ID = 3 THEN CONVERT(TINYINT, ONAY) END),
    user4 = MAX(CASE WHEN ONAY_ID = 4 THEN CONVERT(TINYINT, ONAY) END)
FROM dbo.tablename
WHERE sup_RECno = 1
GROUP BY sip_RECno;

SELECT sip_RECno, 
    user1 = MAX(CASE WHEN ONAY_ID = 1 THEN ONAY END),
    user2 = MAX(CASE WHEN ONAY_ID = 2 THEN ONAY END),
    user3 = MAX(CASE WHEN ONAY_ID = 3 THEN ONAY END),
    user4 = MAX(CASE WHEN ONAY_ID = 4 THEN ONAY END)
FROM dbo.tablename
GROUP BY sip_RECno
WHERE sup_RECno = 1;

SELECT sip_RECno, 
    user1 = MAX(CASE WHEN ONAY_ID = 1 THEN ONAY END),
    user2 = MAX(CASE WHEN ONAY_ID = 2 THEN ONAY END),
    user3 = MAX(CASE WHEN ONAY_ID = 3 THEN ONAY END),
    user4 = MAX(CASE WHEN ONAY_ID = 4 THEN ONAY END)
FROM dbo.tablename
WHERE sup_RECno = 1
GROUP BY sip_RECno;