externals/ownfoil carries a nested submodule pointing at a1ex4/NSTools, and
that repository is gone - GitHub returns 404, so git falls through to asking
for credentials and `git clone --recursive` aborts before any of the tree is
usable. It fails for everyone, on every platform; the only reason it has not
been noticed is that an existing checkout never re-initialises it.
Nothing in the build refers to ownfoil. It is a separate web application that
was vendored in, not a dependency: no CMakeLists mentions it, and removing it
changes nothing that compiles. The other 38 submodule URLs all resolve.
Douglas Whittingham
d5a97a2d73