Move -I option from CXXFLAGS to INCS; this fixes the error reported by Panayotis Papasotiriou.
Move -I option from CXXFLAGS to INCS; this fixes the error reported by
Panayotis Papasotiriou.

grzegorzmazur/yacas,qwert2003/yacas,qwert2003/yacas,MateuszSnamina/yacas,grzegorzmazur/yacas,MateuszSnamina/yacas,martanoga/yacas,qwert2003/yacas,martanoga/yacas,martanoga/yacas,tomaszkrysiuk/yacas,MateuszSnamina/yacas,qwert2003/yacas,martanoga/yacas,tomaszkrysiuk/yacas,grzegorzmazur/yacas,martanoga/yacas,MateuszSnamina/yacas,MateuszSnamina/yacas,tomaszkrysiuk/yacas,tomaszkrysiuk/yacas,grzegorzmazur/yacas,qwert2003/yacas,tomaszkrysiuk/yacas,grzegorzmazur/yacas,martanoga/yacas,qwert2003/yacas,grzegorzmazur/yacas,tomaszkrysiuk/yacas,grzegorzmazur/yacas,MateuszSnamina/yacas,martanoga/yacas,tomaszkrysiuk/yacas,qwert2003/yacas,MateuszSnamina/yacas