engr_at
struct engr *ep = engr_at(x,y);
struct engr *ep = engr_at(x,y);
struct engr *ep = engr_at(x,y);
if ((ep = engr_at(x,y)))
struct engr *ep, *oep = engr_at(u.ux,u.uy);
struct engr *engr_at(xchar, xchar);