Makefile: turns on more compiler warnings
Makefile: turns on more compiler warnings

cvfish/vlfeat,qubick/vlfeat,erexhepa/vlfeat,richarddzh/vlfeat,WangDequan/vlfeat,hongzhili/vlfeat,rxl194/vlfeat,richarddzh/vlfeat,cvfish/vlfeat,rxl194/vlfeat,vlfeat/vlfeat,mylxiaoyi/vlfeat,CansenJIANG/vlfeat,j-bo/vlfeat,hongzhili/vlfeat,vlfeat/vlfeat,richarddzh/vlfeat,erexhepa/vlfeat,erexhepa/vlfeat,j-bo/vlfeat,rxl194/vlfeat,qubick/vlfeat,richarddzh/vlfeat,WangDequan/vlfeat,hongzhili/vlfeat,hongzhili/vlfeat,richarddzh/vlfeat,CansenJIANG/vlfeat,qubick/vlfeat,vlfeat/vlfeat,WangDequan/vlfeat,CansenJIANG/vlfeat,mylxiaoyi/vlfeat,cvfish/vlfeat,vlfeat/vlfeat,rxl194/vlfeat,WangDequan/vlfeat,qubick/vlfeat,hongzhili/vlfeat,j-bo/vlfeat,CansenJIANG/vlfeat,CansenJIANG/vlfeat,j-bo/vlfeat,erexhepa/vlfeat,cvfish/vlfeat,j-bo/vlfeat,cvfish/vlfeat,mylxiaoyi/vlfeat,rxl194/vlfeat,vlfeat/vlfeat,qubick/vlfeat,WangDequan/vlfeat,erexhepa/vlfeat,WangDequan/vlfeat,erexhepa/vlfeat,mylxiaoyi/vlfeat,rxl194/vlfeat,mylxiaoyi/vlfeat,mylxiaoyi/vlfeat,cvfish/vlfeat,qubick/vlfeat,CansenJIANG/vlfeat,vlfeat/vlfeat,richarddzh/vlfeat,hongzhili/vlfeat