cmake fix for older cmake
cmake fix for older cmake

AG this wasn't needed on cmake 2.8.10.2 but did not make any
problem either

Signed-off-by: Edwin van den Oetelaar <ac045c22b3018ff51cae0fcad30934ef50aa22cb@gmail.com>
tn0502/libwebsockets,SoapyMan/libwebsockets,mralexgray/libwebsockets-xcode,maws/libwebsockets,pankona/libwebsockets,antmicro/libwebsockets,PureSwift/libwebsockets,RobertoMalatesta/libwebsockets,GroundControl-Solutions/libwebsockets,kaostao/libwebsockets,sartura/libwebsockets,wenqiwooo/syslog-libwebsockets,sanyaade-teachings/libwebsockets,tn0502/libwebsockets,turbulenz/libwebsockets,gameclosure/libwebsockets,ralight/libwebsockets,kaostao/libwebsockets,RobertoMalatesta/libwebsockets,dumganhar/libwebsockets,pebble/libwebsockets,GroundControl-Solutions/libwebsockets,IOPOINT/libwebsockets,pombredanne/libwebsockets,IOPOINT/libwebsockets,pankona/libwebsockets,ralight/libwebsockets,peeracle/libwebsockets,tn0502/libwebsockets,canopy-project/libwebsockets-canopy,PureSwift/libwebsockets,DaYeSquad/libwebsockets,pombredanne/libwebsockets,gameclosure/libwebsockets,Chilledheart/libwebsockets,JoakimSoderberg/libwebsockets,PureSwift/libwebsockets,jmillan/libwebsockets,DaYeSquad/libwebsockets,pebble/libwebsockets,giovanni-liboni/libwebsockets,sartura/libwebsockets,abligh/libwebsockets,dtebbs/libwebsockets,SoapyMan/libwebsockets,dtebbs/libwebsockets,weimingtom/libwebsockets,sanyaade-teachings/libwebsockets,SoapyMan/libwebsockets,pebble/libwebsockets,SoapyMan/libwebsockets,GroundControl-Solutions/libwebsockets,sanyaade-teachings/libwebsockets,dtebbs/libwebsockets,dumganhar/libwebsockets,mushroomgithub/libwebsockets,DaYeSquad/libwebsockets,JoakimSoderberg/libwebsockets,dumganhar/libwebsockets,sartura/libwebsockets,mushroomgithub/libwebsockets,weimingtom/libwebsockets,ralight/libwebsockets,mralexgray/libwebsockets-xcode,GroundControl-Solutions/libwebsockets,peeracle/libwebsockets,sartura/libwebsockets,maws/libwebsockets,lukasz-skalski/libwebsockets,mushroomgithub/libwebsockets,gameclosure/libwebsockets,Chilledheart/libwebsockets,mralexgray/libwebsockets-xcode,cambridgehackers/libwebsockets,sartura/libwebsockets,turbulenz/libwebsockets,giovanni-liboni/libwebsockets,pankona/libwebsockets,JoakimSoderberg/libwebsockets,mralexgray/libwebsockets-xcode,tn0502/libwebsockets,jmillan/libwebsockets,peeracle/libwebsockets,kaostao/libwebsockets,wenqiwooo/syslog-libwebsockets,Chilledheart/libwebsockets,cambridgehackers/libwebsockets,sanyaade-teachings/libwebsockets,dumganhar/libwebsockets,giovanni-liboni/libwebsockets,ralight/libwebsockets,pombredanne/libwebsockets,DaYeSquad/libwebsockets,wenqiwooo/syslog-libwebsockets,jmillan/libwebsockets,sartura/libwebsockets,pombredanne/libwebsockets,IOPOINT/libwebsockets,sartura/libwebsockets,abligh/libwebsockets,ralight/libwebsockets,PureSwift/libwebsockets,antmicro/libwebsockets,antmicro/libwebsockets,pebble/libwebsockets,kaostao/libwebsockets,pankona/libwebsockets,weimingtom/libwebsockets,RobertoMalatesta/libwebsockets,canopy-project/libwebsockets-canopy,weimingtom/libwebsockets,peeracle/libwebsockets,gameclosure/libwebsockets,lukasz-skalski/libwebsockets,DaYeSquad/libwebsockets,jmillan/libwebsockets,maws/libwebsockets,giovanni-liboni/libwebsockets,turbulenz/libwebsockets,abligh/libwebsockets,abligh/libwebsockets,RobertoMalatesta/libwebsockets,maws/libwebsockets,dtebbs/libwebsockets,antmicro/libwebsockets,PureSwift/libwebsockets,Chilledheart/libwebsockets,lukasz-skalski/libwebsockets,cambridgehackers/libwebsockets,JoakimSoderberg/libwebsockets,cambridgehackers/libwebsockets,mushroomgithub/libwebsockets,canopy-project/libwebsockets-canopy,peeracle/libwebsockets,SoapyMan/libwebsockets,GroundControl-Solutions/libwebsockets,lukasz-skalski/libwebsockets,dumganhar/libwebsockets,wenqiwooo/syslog-libwebsockets