fix warnings in gcc
fix warnings in gcc

PedroTrujilloV/chrono,jcmadsen/chrono,rserban/chrono,jcmadsen/chrono,andrewseidl/chrono,armanpazouki/chrono,armanpazouki/chrono,tjolsen/chrono,Milad-Rakhsha/chrono,Milad-Rakhsha/chrono,projectchrono/chrono,tjolsen/chrono,dariomangoni/chrono,hsu/chrono,dariomangoni/chrono,Milad-Rakhsha/chrono,hsu/chrono,andrewseidl/chrono,tjolsen/chrono,amelmquist/chrono,rserban/chrono,hsu/chrono,amelmquist/chrono,Milad-Rakhsha/chrono,andrewseidl/chrono,amelmquist/chrono,jcmadsen/chrono,amelmquist/chrono,andrewseidl/chrono,dariomangoni/chrono,amelmquist/chrono,rserban/chrono,rserban/chrono,PedroTrujilloV/chrono,PedroTrujilloV/chrono,hsu/chrono,projectchrono/chrono,hsu/chrono,rserban/chrono,amelmquist/chrono,projectchrono/chrono,PedroTrujilloV/chrono,Bryan-Peterson/chrono,dariomangoni/chrono,projectchrono/chrono,jcmadsen/chrono,jcmadsen/chrono,andrewseidl/chrono,Bryan-Peterson/chrono,rserban/chrono,PedroTrujilloV/chrono,tjolsen/chrono,projectchrono/chrono,armanpazouki/chrono,armanpazouki/chrono,dariomangoni/chrono,rserban/chrono,jcmadsen/chrono,dariomangoni/chrono,armanpazouki/chrono,tjolsen/chrono,Bryan-Peterson/chrono,armanpazouki/chrono,Bryan-Peterson/chrono,Bryan-Peterson/chrono,projectchrono/chrono,jcmadsen/chrono,Milad-Rakhsha/chrono,Milad-Rakhsha/chrono