this is a million times faster
new only in rust 1.68, and fails on older versions,
but we have only latest in aports and don't support anything else, so
it's okay.
this does not download deps that won't be used for the default build
target (the ctarget we are building for implicitly).
this makes quite a few fetches faster.. because a ton of crates download
a 10mb "windows-sys" that is never used, amongst other things.
maybe breaks a thing or two.
