Commit 5b7fb9c402 incorrectly removed the trailing null from
`g_descent_version`. Add an explicit null, since list initialization
does not imply a null.
Fixes: 5b7fb9c402 ("Reduce use of quotes for passing vers_id defines")
Windows shells interpret quoting differently from Linux shells, causing
some of the generated strings to have ugly escape sequences in them.
Switch to passing the defined values as lists of character codes, so
that no quoting is needed. This makes the command line uglier, but
produces more readable strings in the generated program.
For each link given as http://, verify that the site is accessible over
https:// and, if so, switch to it. These domains were converted:
* llvm.org
* clang.llvm.org
* en.cppreference.com
* www.dxx-rebirth.com
* www.libsdl.org
* www.scons.org
