Fix for configure attempting to link boost_system even with boost 1.49 or earlier.
Fix for configure attempting to link boost_system even with boost 1.49 or earlier.

FLOWERCLOUD/povray,c-lipka/povray,LogicalKnight/povray,wfpokorny/povray,LogicalKnight/povray,UberPOV/UberPOV,LogicalKnight/povray,c-lipka/povray,LogicalKnight/povray,wfpokorny/povray,davidgiven/povray,eblanca/povray,POV-Ray/povray,LeForgeron/povray,UberPOV/UberPOV,FLOWERCLOUD/povray,FLOWERCLOUD/povray,LeForgeron/povray,POV-Ray/povray,FLOWERCLOUD/povray,LogicalKnight/povray,wfpokorny/povray,c-lipka/povray,FLOWERCLOUD/povray,LogicalKnight/povray,BentSm/povray,UberPOV/UberPOV,LeForgeron/povray,UberPOV/UberPOV,FLOWERCLOUD/povray,davidgiven/povray,POV-Ray/povray,BentSm/povray,UberPOV/UberPOV,LeForgeron/povray,c-lipka/povray,LogicalKnight/povray,FLOWERCLOUD/povray,UberPOV/UberPOV,FLOWERCLOUD/povray,eblanca/povray,wfpokorny/povray,davidgiven/povray,LeForgeron/povray,LeForgeron/povray,davidgiven/povray,POV-Ray/povray,davidgiven/povray,davidgiven/povray,POV-Ray/povray,POV-Ray/povray,LogicalKnight/povray,BentSm/povray,wfpokorny/povray,BentSm/povray,wfpokorny/povray,LeForgeron/povray,eblanca/povray,davidgiven/povray,FLOWERCLOUD/povray,POV-Ray/povray,LeForgeron/povray,wfpokorny/povray,UberPOV/UberPOV,davidgiven/povray,eblanca/povray,davidgiven/povray,LogicalKnight/povray