update of scripts for native windows agent

scripts/windows_agent_bootstrap.ps1

@@ -27,7 +27,7 @@ choco install git
 
 Write-Host "Mounting result storage..."
 Install-WindowsFeature NFS-Client
-net use E: \\results.local\exports
+net use E: \\results.local\exports /PERSISTENT:YES
 
 Set-Location D:\
 git clone https://github.com/google/llvm-premerge-checks

scripts/windows_agent_install.ps1

@@ -12,9 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+. ${PSScriptRoot}\common.ps1
 
 Write-Host "Installing Visual Studio build tools..."
-choco install visualcpp-build-tools --version 15.0.26228.20170424 -y --params "'/IncludeOptional'"
+choco install -y visualcpp-build-tools --version 15.0.26228.20170424 -y --params "'/IncludeOptional'"
 Write-Host 'Waiting for Visual C++ Build Tools to finish'
 Wait-Process -Name vs_installer
 
@@ -25,9 +26,9 @@ choco install -y git python2 ninja gnuwin cmake
 pip install psutil
 
 Write-Host "Setting environment variables..."
-$Env:PYTHONIOENCODING=UTF-8
-$Env:path = $Env:path + ';c:\Program Files (x86)\GnuWin32\bin;C:\Program Files\CMake\bin'
-
+[System.Environment]::SetEnvironmentVariable('PYTHONIOENCODING', 'UTF-8', [System.EnvironmentVariableTarget]::User)
+$oldpath=[System.Environment]::GetEnvironmentVariable('path',[System.EnvironmentVariableTarget]::User)
+[System.Environment]::SetEnvironmentVariable('path', $oldpath + 'c:\Program Files (x86)\GnuWin32\bin;C:\Program Files\CMake\bin', [System.EnvironmentVariableTarget]::User)
 # support long file names during git checkout
 Write-Host "Setting git config..."
 git config --system core.longpaths true

scripts/windows_agent_start.ps1

@@ -0,0 +1,22 @@
+# Copyright 2019 Google LLC
+#
+# Licensed under the the Apache License v2.0 with LLVM Exceptions (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://llvm.org/LICENSE.txt
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+. ${PSScriptRoot}\common.ps1
+
+$JENKINS_SERVER="jenkins.local"
+$AGENT_ROOT="D:\"
+$SWARM_PLUGIN_JAR="C:\jenkins\swarm-client.jar"
+
+java -jar ${SWARM_PLUGIN_JAR} -master http://${JENKINS_SERVER}:8080 -executors 1 -fsroot ${AGENT_ROOT} -labels windows