[base] Fix `ft_corner_orientation'. Remove casting from `FT_Long' to `FT_Int' that might change the sign of the return value and make it faster too. * src/base/ftcalc.c (ft_corner_orientation): On 32-bit systems, stay with 32-bit arithmetic when safe. Use plain math on 64-bit systems. * src/pshinter/pshalgo.c: Remove old unused code.