unsigned char by default compiler compatibility
unsigned char by default compiler compatibility

http://ml.libwebsockets.org/pipermail/libwebsockets/2015-March/001705.html

Signed-off-by: Andy Green <b471f5a494de34531c9e5a6e15abda71edd49104@linaro.org>
mushroomgithub/libwebsockets,ralight/libwebsockets,cambridgehackers/libwebsockets,dumganhar/libwebsockets,jmillan/libwebsockets,ralight/libwebsockets,mushroomgithub/libwebsockets,sartura/libwebsockets,SoapyMan/libwebsockets,dumganhar/libwebsockets,gameclosure/libwebsockets,SoapyMan/libwebsockets,ralight/libwebsockets,pombredanne/libwebsockets,pombredanne/libwebsockets,PureSwift/libwebsockets,jmillan/libwebsockets,sanyaade-teachings/libwebsockets,dumganhar/libwebsockets,peeracle/libwebsockets,sartura/libwebsockets,ralight/libwebsockets,sartura/libwebsockets,gameclosure/libwebsockets,tn0502/libwebsockets,JoakimSoderberg/libwebsockets,RobertoMalatesta/libwebsockets,maws/libwebsockets,tn0502/libwebsockets,PureSwift/libwebsockets,PureSwift/libwebsockets,wenqiwooo/syslog-libwebsockets,sartura/libwebsockets,peeracle/libwebsockets,Chilledheart/libwebsockets,wenqiwooo/syslog-libwebsockets,RobertoMalatesta/libwebsockets,wenqiwooo/syslog-libwebsockets,pankona/libwebsockets,PureSwift/libwebsockets,mushroomgithub/libwebsockets,pankona/libwebsockets,GroundControl-Solutions/libwebsockets,mushroomgithub/libwebsockets,maws/libwebsockets,gameclosure/libwebsockets,pombredanne/libwebsockets,GroundControl-Solutions/libwebsockets,jmillan/libwebsockets,ralight/libwebsockets,sartura/libwebsockets,SoapyMan/libwebsockets,dumganhar/libwebsockets,pankona/libwebsockets,sartura/libwebsockets,sartura/libwebsockets,JoakimSoderberg/libwebsockets,JoakimSoderberg/libwebsockets,gameclosure/libwebsockets,cambridgehackers/libwebsockets,peeracle/libwebsockets,Chilledheart/libwebsockets,pombredanne/libwebsockets,sanyaade-teachings/libwebsockets,maws/libwebsockets,RobertoMalatesta/libwebsockets,Chilledheart/libwebsockets,GroundControl-Solutions/libwebsockets,sanyaade-teachings/libwebsockets,JoakimSoderberg/libwebsockets,peeracle/libwebsockets,SoapyMan/libwebsockets,peeracle/libwebsockets,cambridgehackers/libwebsockets,RobertoMalatesta/libwebsockets,dumganhar/libwebsockets,jmillan/libwebsockets,cambridgehackers/libwebsockets,pankona/libwebsockets,SoapyMan/libwebsockets,sanyaade-teachings/libwebsockets,GroundControl-Solutions/libwebsockets,tn0502/libwebsockets,PureSwift/libwebsockets,maws/libwebsockets,Chilledheart/libwebsockets,GroundControl-Solutions/libwebsockets,tn0502/libwebsockets,wenqiwooo/syslog-libwebsockets