New MSVC property sheet for Multi-threaded XPDEV builds and usage:

defines XPDEV_THREAD_SAFE (not currently used in Windows builds) and
LINK_LIST_THREADSAFE (notice the inconsistent use of underscore :-)

src/xpdev/xpdev_mt.vcxproj

@@ -34,12 +34,14 @@
     <Import Project="$(VCTargetsPath)Microsoft.CPP.UpgradeFromVC60.props" />
     <Import Project="..\build\undeprecate.props" />
     <Import Project="..\build\target_ia32.props" />
+    <Import Project="xpdev_mt.props" />
   </ImportGroup>
   <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="PropertySheets">
     <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
     <Import Project="$(VCTargetsPath)Microsoft.CPP.UpgradeFromVC60.props" />
     <Import Project="..\build\undeprecate.props" />
     <Import Project="..\build\target_ia32.props" />
+    <Import Project="xpdev_mt.props" />
   </ImportGroup>
   <PropertyGroup Label="UserMacros" />
   <PropertyGroup>