Patched stm package for debugging

Features

• STM transactions will include a stacktrace (no more endless hunting for where a "blocked indefinitely" exception is coming from)
• TVar and TMVar have a Show instance that can be used to used to identity and distinguish variables.

Usage

Add the following to your cabal.project file:

source-repository-package
  type: git
  location: https://github.com/edsko/stm-debug
  tag: edsko/instrument-for-debugging
  subdir: . assignid patched/async patched/tasty/core patched/unliftio/unliftio

allow-newer: stm