Hi Guix,

I have missed using the rust tools I use outside of Guix. Ripgrep was the
first one I could build thanks to the work on the rust build system.

Of course, it required adding over 200 dependencies.

Some of these have cyclic dependencies, as you all know. What I understand
is that the rust community is OK with including cyclic dependencies as test
dependencies.  I am actually seeing how useful that is. Consider the system
tests in the guix repository. Certainly that would require including guix
as a dependency to guix.

I also left the cargo inputs and dev inputs commented out just in case
someone wants to put them back in the future and to give a sense of the
topological order of the patches.

Having imported ripgrep some months ago, some of these dependencies will
require updates, but I did not want to break the working version of ripgrep
at the end of the line.  Otherwise I have fixed the other lint errors and I
have been using ripgrep for several months.

- John