A note about the source: upstream doesn't do release tarballs. The source
is only available via git (older versions used svn). What I had to do
to get the 1.8.2 source: download the windows binary, run strings on it
to find the git commit hash, then clone the git repo and check out that
revision. Then I spent a couple hours trying to patch it so it would
compile, then said "hell with it" and used the latest git (which compiles
and runs fine). So my VERSION is a lie, which might cause problems if
you want to play multiplayer with people using the windows 1.8.2 binary
release. Blame upstream, not me.

For reference, the windows binary's commit hash is:
cbdfa61619ee99db541361b8ca174d58848e4

The one in my tarball is: 4a23b97963d8e57d4c62efa41323910df903d

gzdoom's build process requires it to be built from a git checkout.
It uses the .git stuff to define a GIT_REVISION variable. That's why
the source tarball contains a .git/ dir. If it doesn't, you end up with
a gzdoom that announces itself as revision <unknown> (shows up in the
console and titlebar of the window). Also the revision is used to check
savegame compatibility, so it's not just cosmetic.