FS-11288: [Build-System] Refactor WIX project to not miss modules in msi on slow machines. Move Windows build logic from legacy util.vbs to modern props. Fix sound packages improper extraction. Fix multiprocessor build under msbuild.

w32/download_libav.props

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ImportGroup Label="PropertySheets">
+    <Import Project="downloadpackage.task" Condition=" '$(downloadpackagetask_Imported)' == '' " />
+  </ImportGroup>
+  <PropertyGroup>
+    <libavPropsImported>true</libavPropsImported>
+  </PropertyGroup>
+
+  <!--
+       Download Target.
+       Name must be unique.
+       By design, targets are executed only once per project.
+
+       Usage:
+
+       package: URI
+
+       expectfileordirectory: Skips the download and extraction if exists
+
+       outputfolder: Folder to store a downloaded file.
+                     By default "$(BaseDir)libs", if empty
+
+       outputfilename: If not empty, overrides filename from URI.
+                       .exe files don't get extracted
+
+       extractto: Folder to extract an archive to
+   -->
+
+  <Target Name="libavDownloadTarget" BeforeTargets="CustomBuild" DependsOnTargets="7za">
+      <DownloadPackageTask
+           package="http://files.freeswitch.org/downloads/libs/libav-12.tar.bz2"
+           expectfileordirectory="$(BaseDir)libs\libav\avconv.h"
+           outputfolder=""
+           outputfilename=""
+           extractto="$(BaseDir)libs\"
+      />
+  </Target>
+
+</Project>