Allow tests on aarch64-linux, etc. (#234)

Author: srid

test/common.sh

@@ -5,11 +5,7 @@ function logHeader {
   echo -e "\n||| $@"
 }
 
-if [ "$(uname)" == "Darwin" ]; then
-  SYSTEM=aarch64-darwin
-else
-  SYSTEM=x86_64-linux
-fi
+SYSTEM=$(nix show-config | grep 'system =' | nix run nixpkgs#gawk '{print $3}')
 
 DIR_OF_COMMON_SH="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 HASKELL_FLAKE=${DIR_OF_COMMON_SH}/..