Add build environment script (with partition support)

eng/core-sdk-build-env.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+#
+# Copyright (c) .NET Foundation and contributors. All rights reserved.
+# Licensed under the MIT license. See LICENSE file in the project root for full license information.
+#
+
+SOURCE="${BASH_SOURCE[0]}"
+while [ -h "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
+  DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"
+  SOURCE="$(readlink "$SOURCE")"
+  [[ "$SOURCE" != /* ]] && SOURCE="$DIR/$SOURCE" # if $SOURCE was a relative symlink, we need to resolve it relative to the path where the symlink file was located
+done
+
+REPO_ROOT="$( cd -P "$( dirname "$SOURCE" )/../" && pwd )"
+
+arcade_partition=
+
+while [[ $# > 0 ]]; do
+  opt="$(echo "${1/#--/-}" | awk '{print tolower($0)}')"
+  case "$opt" in
+    -partition)
+      arcade_partition=$2
+      shift
+      ;;
+  esac
+
+  shift
+done
+
+export ARCADE_PARTITION=$arcade_partition
+
+if [[ ! -z "$arcade_partition" ]]; then
+  arcade_partition_suffix="-$arcade_partition"
+fi
+
+export PATH=$REPO_ROOT/.dotnet$arcade_partition_suffix:$PATH
+export DOTNET_INSTALL_DIR=$REPO_ROOT/.dotnet$arcade_partition_suffix
+export ArtifactsDir=$REPO_ROOT/artifacts$arcade_partition_suffix/
+
+export DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1
+export DOTNET_MULTILEVEL_LOOKUP=0