kpsewhich could not be found because GTK on windows needs to use the
`gspawn-win32-helper` program to spawn processes.
This commit also improves kpsewhich error reporting.
The issue seems to be that libcrypto and libssl are already included in
the Windows CI image by default, causing them to not be copied. This patch
ensures that they're copied if the application is linked with the system
libcrypto/ssl.
Bryan Tan
Andreas Butti
Andreas Butti