Shorten copy&paste commands needed to get a Windows dev env

by integrating Enable-WindowsOptionalFeature ... into doc/win-dev.ps1.

doc/21-development.md

@@ -1736,12 +1736,7 @@ and don't care for the details,
 
 1. ensure there are 35 GB free space on C:
 2. run the following in an administrative Powershell:
-    1. Windows Server only:
+   `powershell -nop -ep bypass -c "iex (iwr 'https://raw.githubusercontent.com/Icinga/icinga2/master/doc/win-dev.ps1')"`
-       `Enable-WindowsOptionalFeature -FeatureName NetFx3ServerFeatures -Online`
-    2. `Enable-WindowsOptionalFeature -FeatureName NetFx3 -Online`
-       (reboot when asked!)
-    3. `powershell -NoProfile -ExecutionPolicy Bypass -Command "Invoke-Expression (New-Object Net.WebClient).DownloadString('https://raw.githubusercontent.com/Icinga/icinga2/master/doc/win-dev.ps1')"`
-       (will take some time)
 
 This installs everything needed for cloning and building Icinga 2
 on the command line (Powershell) as follows:

doc/win-dev.ps1

@@ -57,6 +57,19 @@ function Install-Exe {
 }
 
 
+function Needs-WinFeatureRestart($feature) {
+	(Enable-WindowsOptionalFeature -FeatureName $feature -Online).RestartNeeded
+}
+
+
+$isServer = (Get-CimInstance -ClassName Win32_OperatingSystem).Caption -match 'Windows Server'
+$serverNeedsRestart = $isServer -and (Needs-WinFeatureRestart NetFx3ServerFeatures)
+$needsRestart = Needs-WinFeatureRestart NetFx3
+
+if ($serverNeedsRestart -or $needsRestart) {
+    throw 'Restart needed'
+}
+
 try {
 	Get-Command choco
 } catch {