It seems these changes are not enough. The definition of POLY_CIRC_RADIUS_ADJ (in polygon.h) is also incorrect. The correct definition is:
#define POLY_CIRC_RADIUS_ADJ (1.0/cos(M_PI / POLY_CIRC_SEGS_F))
It seems these changes are not enough. The definition of POLY_CIRC_ RADIUS_ ADJ (in polygon.h) is also incorrect. The correct definition is:
#define POLY_CIRC_ RADIUS_ ADJ (1.0/cos(M_PI / POLY_CIRC_SEGS_F))