Using indexes into the line instead of Vec<u8>s means we don't have to copy
the line to store the fields (indexes instead of slices because it avoids
self-referential structs). Using memchr also empirically saves a lot of
intermediate allocations.
- Change the main! proc_macro to a bin! macro_rules macro.
- Reexport uucore_procs from uucore
- Make utils to not import uucore_procs directly
- Remove the `syn` dependency and don't parse proc_macro input (hopefully for faster compile times)
This makes clap wrap the help text according to the terminal width,
which improves readability for terminal widths < 120 chars,
because clap defaults to a width of 120 chars without this feature.
- refactor internal version specifications to be ">=M.m.p" (where M.m.p is *already published*)
## [why]
Loosening internal version dependencies decreases the coupling between packages such
that packages can be published in a looser order. It allows the packages to be version
updated and published in tandem (ie, by using `cargo workspace ...`). Once published,
the internal versions can then be updated (again, to an *already published* package
version), as needed.
