fix building with root paths that contain spaces (#10219)

eng/Build.ps1

@@ -297,8 +297,8 @@ function BuildCompiler() {
     if ($bootstrapTfm -eq "netcoreapp3.1") {
         $dotnetPath = InitializeDotNetCli
         $dotnetExe = Join-Path $dotnetPath "dotnet.exe"
-        $fscProject = "$RepoRoot\src\fsharp\fsc\fsc.fsproj"
-        $fsiProject = "$RepoRoot\src\fsharp\fsi\fsi.fsproj"
+        $fscProject = "`"$RepoRoot\src\fsharp\fsc\fsc.fsproj`""
+        $fsiProject = "`"$RepoRoot\src\fsharp\fsi\fsi.fsproj`""
 
         $argNoRestore = if ($norestore) { " --no-restore" } else { "" }
         $argNoIncremental = if ($rebuild) { " --no-incremental" } else { "" }

eng/build-utils.ps1

@@ -239,7 +239,7 @@ function Make-BootstrapBuild() {
     # prepare FsLex and Fsyacc and AssemblyCheck
     $dotnetPath = InitializeDotNetCli
     $dotnetExe = Join-Path $dotnetPath "dotnet.exe"
-    $buildToolsProject = "$RepoRoot\src\buildtools\buildtools.proj"
+    $buildToolsProject = "`"$RepoRoot\src\buildtools\buildtools.proj`""
 
     $argNoRestore = if ($norestore) { " --no-restore" } else { "" }
     $argNoIncremental = if ($rebuild) { " --no-incremental" } else { "" }
@@ -256,7 +256,7 @@ function Make-BootstrapBuild() {
     Copy-Item "$ArtifactsDir\bin\AssemblyCheck\$bootstrapConfiguration\netcoreapp3.1" -Destination "$dir\AssemblyCheck" -Force  -Recurse
 
     # prepare compiler
-    $protoProject = "$RepoRoot\proto.proj"
+    $protoProject = "`"$RepoRoot\proto.proj`""
     $args = "build $protoProject -c $bootstrapConfiguration -v $verbosity -f $bootstrapTfm" + $argNoRestore + $argNoIncremental
     if ($binaryLog) {
         $logFilePath = Join-Path $LogDir "protoBootstrapLog.binlog"