polygon.c: In function ‘spherepoly_in’:
polygon.c:827:3: error: ISO C90 forbids variable length array ‘arr’ [-Werror=vla]
  827 |   SPoint  arr[nelem];
      |   ^~~~~~
polygon.c: In function ‘spherepoly_area’:
polygon.c:895:2: error: ISO C90 forbids variable length array ‘s’ [-Werror=vla]
  895 |  SPoint  s[poly->npts + 2];
      |  ^~~~~~
cc1: some warnings being treated as errors
make: *** [<builtin>: polygon.o] Error 1