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.
The cargo vars are now set in abuild.conf by default.
Newlines done with:
find . -name APKBUILD -exec sed -i '/^$/N;/^\n$/D' {} \;
See also: https://stackoverflow.com/a/4522043