[build.ps1] fix misuse of varibles in Extract-Toolchain

Author: stevapple

utils/build.ps1

@@ -700,16 +700,16 @@ function Fetch-Dependencies {
         $installerWriteTime = (Get-Item $source).LastWriteTime
         $extractedWriteTime = (Get-Item $destination).LastWriteTime
         if ($installerWriteTime -le $extractedWriteTime) {
-            Write-Output "'$ToolchainName' is already extracted and up to date."
+            Write-Output "'$InstallerExeName' is already extracted and up to date."
             return
         }
     }
 
-    Write-Output "Extracting '$ToolchainName' ..."
+    Write-Output "Extracting '$InstallerExeName' ..."
 
     # The new runtime MSI is built to expand files into the immediate directory. So, setup the installation location.
     New-Item -ItemType Directory -ErrorAction Ignore $BinaryCache\toolchains\$PinnedToolchain\LocalApp\Programs\Swift\Runtimes\$(Get-PinnedToolchainVersion)\usr\bin | Out-Null
-    Invoke-Program $BinaryCache\WiX-$WiXVersion\tools\net6.0\any\wix.exe -- burn extract $BinaryCache\$ToolchainName.exe -out $BinaryCache\toolchains\ -outba $BinaryCache\toolchains\
+    Invoke-Program $BinaryCache\WiX-$WiXVersion\tools\net6.0\any\wix.exe -- burn extract $BinaryCache\$InstallerExeName -out $BinaryCache\toolchains\ -outba $BinaryCache\toolchains\
     Get-ChildItem "$BinaryCache\toolchains\WixAttachedContainer" -Filter "*.msi" | ForEach-Object {
       $LogFile = [System.IO.Path]::ChangeExtension($_.Name, "log")
       $TARGETDIR = if ($_.Name -eq "rtl.msi") { "$BinaryCache\toolchains\$ToolchainName\LocalApp\Programs\Swift\Runtimes\$(Get-PinnedToolchainVersion)\usr\bin" } else { "$BinaryCache\toolchains\$ToolchainName" }