Nim 1.6.8 release candidate

@miran, it is necessary to include this [PR](https://github.com/nim-lang/Nim/pull/19959). Without it version 1.6.8 will be broken for vcc and clangcl on Windows.

Nim 1.6.8 release candidate

Can this regression about PEG be fixed? Thanks.

Nim 1.6.8 release candidate

I'm excited to try this out. Thanks! I'm probably too late, but would it be possible to get included?

Nim 1.6.8 release candidate

Here is the first release candidate for Nim 1.6.8, available from our nightly builds: If you're using Choosenim, you should be able to get this RC by doing: chooseni