[Agda] [ANN] Agda-2.6.4.3 release candidate 1

[Andreas Abel]

Dear all,

Ok, after the botched release of Agda 2.6.4.2 there is release candidate 
for Agda 2.6.4.3.

Changes over Agda 2.6.4.2 are two fixes:

- [Issue #7148](https://github.com/agda/agda/issues/7148):
   Regression in 2.6.4.2 concerning `with`

- [Issue #7150](https://github.com/agda/agda/issues/7150):
   Regression in 2.6.4 in `rewrite` with instances

# GHC supported versions

Agda 2.6.4.3 RC 1 has been tested with GHC 9.8.1, GHC 9.6.4, 9.4.8, 
9.2.8, 9.0.2, 8.10.7, 8.8.4 and 8.6.5 on Linux, macOS and Windows.

# Installation

Agda 2.6.4.3 RC 1 can be installed using cabal-install or stack:

1. Getting the release candidate

       $ cabal get 
https://hackage.haskell.org/package/Agda-2.6.4.3/candidate/Agda-2.6.4.3.tar.gz
       $ cd Agda-2.6.4.3

2. a. Using cabal-install

       $ cabal install -f +optimise-heavily -f +enable-cluster-counting

2. b. Using stack

       $ stack --stack-yaml stack-a.b.c.yaml install --flag 
Agda:optimise-heavily --flag Agda:enable-cluster-counting

replacing `a.b.c` with your version of GHC.

The flags mean:

   - optimise-heavily:
     Turn on extra optimisation for a faster Agda.
     Takes large resources during compilation of Agda.

   - enable-cluster-counting:
     Enable unicode clusters for alignment in the LaTeX backend.
     Requires the ICU lib to be installed and known to pkg-config.

These flags can be dropped from the install if causing trouble.

# Standard library

You can use standard library v1.7.3, v2.0 or the `master` branch of the
standard library with Agda 2.6.4.3.  This branch is available at

   https://github.com/agda/agda-stdlib/

# Fixed issues over Agda 2.6.4.2

   https://hackage.haskell.org/package/Agda-2.6.4.3/candidate/changelog

Please test the Agda 2.6.4.3 RC 1 on your developments.
Report problems and regressions to: https://github.com/agda/agda/issues

Andreas, on behalf of the Agda Developers