After a recent update to my Cygwin installation, the convert program
stopped working. It simply exited silently, though I discover with gdb
that it was failing with an unknown exception. It turned out that this
was because of a missing dll, specifically
/usr/X11R6/bin/cygdpstk-1.dll, which also requires
/usr/X11R6/bin/cygdps-1.dll.
A bit more digging and I found that these DLLs used to be part of
package xorg-x11-bin-dlls but has been removed with the latest release -
6.8.99.901-1.
I've fixed the problem for myself by grabbing these DLLs from the
previous version of this package (xorg-x11-bin-dlls-6.8.2.0) and
hand-installing them.
So, as I said, I don't know whether this could be fixed by you or the
x11 maintainers. Any thoughts?