The Qt5Network classes seem to only support OpenSSL, and because OpenSSL
isn't available on windows, we would have to distribute it with the
program to get SSL access working. The problem with that is that
OpenSSL is not GPL-compatible, so we cannot distribute OpenSSL with the
program, which means we have to find a better (and preferably superior)
library for accessing remote files that can use the windows SSPI for our
SSL needs, which comes with the operating system.
Fortunately, libcurl is probably the best library out there, and can be
compiled with SSPI instead of OpenSSL, so we're just going to switch to
libcurl instead. Originally I thought it didn't support SSPI, otherwise
I would have implemented it sooner.
As a side note, this will make it so we'll able to get files from the
internet via plugins, which will be quite useful.
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