** Shares in Saudi Arabian developer Jabal Omar surge 5.8 percent to 80.00 riyals ** Company said on Thursday it had sold residential unitsworth 70.1 million riyals ($18.7 million) ** Will use proceeds to fund further construction ** Stock is main support for Saudi Arabia's stock index, which rises 1.0 percent (Reporting by Olzhas Auyezov; Editing by Andrew Torchia)