bgo#738050 - Handle the case where a list of coordinate pairs has an odd number of elements
bgo#738050 - Handle the case where a list of coordinate pairs has an odd number of elements

Lists of points come in coordinate pairs, but we didn't have any checking for that.
It was possible to try to fetch the 'last' coordinate in a list, i.e. the y coordinate
of an x,y pair, that was in fact missing, leading to an out-of-bounds array read.

In that case, we now reuse the last-known y coordinate.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=738050

Signed-off-by: Federico Mena Quintero <4999915a961edfd7686112c2935288e1266eae14@gnome.org>

GNOME/librsvg,GNOME/librsvg,GNOME/librsvg,GNOME/librsvg