Void-packages: racer is tracking nightly rust

[faulesocke]

The package racer will not build in the recent version any longer since they are now tracking the nightly rust compiler. There are multiple ways to deal with this:

• depend on rustup instead of rust and cargo, and during compilation of racer download a (precompiled!) nightly rust compiler
• package nightly rust
• keep the package in the 2.0.14 version around for some time but drop it eventually - people who require it, can conveniently build it on their own with a single command

I don't feel really good with the first option, since I don't like downloading pre-compiled binaries (even when they are from the same source as the sourcecode is). What are your oppinions?

[maxice8]

i'm for option 3.

I have no desire to keep packages that follow unstable releases and it is easy for people that want it to build it.

[Gottox]

Going for option 3.