Error: lw_dist2d_pt_arc division by zero

[algunenano]

In lw_dist2d_pt_arc, if the point is in the center of the arc a division by zero happens which leads to undefined behaviour.

I've created a PR in Github with the test and changes needed to fix it: ​https://github.com/postgis/postgis/pull/147

[strk]

Please make sure to set Milestone to the oldest affected branch. Great to see unit test included in that PR!

[pramsey]

In 15944:

lw_dist2d_pt_arc division by zero (References #3874)

[pramsey]

In 15945:

lw_dist2d_pt_arc division by zero (References #3874)

[pramsey]

In 15946:

lw_dist2d_pt_arc division by zero (References #3874)

[pramsey]

In 15947:

lw_dist2d_pt_arc division by zero (References #3874)