Windows: Add a helper to cleanly invoke NMake with zlib

Invoke-NMake helper temporarily clears MAKE flags, such as
MAKEFLAGS='-j8', to prevent errors from GNU-style flags and to reduce
flakiness with NMAKE.

The helper is used to build zlib and to prevent:
error U1065: invalid option '-'

Pick-to: 6.8 6.5
Task-number: QTQAINFRA-7363
Change-Id: Ia80216677eba6fd8f8364741b6999e6155d678ab
Reviewed-by: Tero Heikkinen <tero.heikkinen@qt.io>
(cherry picked from commit 0f3d085101)

coin/provisioning/common/windows/helpers.ps1

@@ -382,3 +382,22 @@ function Invoke-MtCommand {
   & $Env:SystemRoot\system32\cmd.exe /c $cmdLine | Write-Output
   Remove-Item $tempFile
 }
+
+function Invoke-NMake {
+    param([string[]]$NmakeArgs)
+    # Temporarily remove MAKE flags for NMAKE process
+    $old = @{
+        MAKEFLAGS  = (Get-Item Env:MAKEFLAGS  -ErrorAction Ignore).Value
+        MFLAGS     = (Get-Item Env:MFLAGS     -ErrorAction Ignore).Value
+        MAKE       = (Get-Item Env:MAKE       -ErrorAction Ignore).Value
+        NMAKEFLAGS = (Get-Item Env:NMAKEFLAGS -ErrorAction Ignore).Value
+    }
+    foreach ($n in $old.Keys) {Remove-Item "Env:$n" -ErrorAction SilentlyContinue}
+    try   {& nmake @NmakeArgs}
+    finally {
+        foreach ($n in $old.Keys) {
+            if ($old[$n]) {Set-EnvironmentVariable -Key "$n" -Value $old[$n]}
+            else {Remove-Item "Env:$n" -ErrorAction SilentlyContinue}
+        }
+    }
+}

coin/provisioning/common/windows/zlib.ps1

@@ -42,8 +42,7 @@ function BuildZlib {
     )
 
     PrepareBuildEnvironment -HostArchitecture $HostArchitecture -TargetArchitecture $TargetArchitecture
-
-    nmake /f $MAKEFILE
+    Invoke-NMake -NmakeArgs @('/f', "$MAKEFILE")
 }
 
 function CopySource {