build.proj

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <ItemGroup>
        <ConfigurationList Condition="  '@(ConfigurationList)' == '' and $(Configuration) != '' " Include="$(Configuration.Split(';'))" />
        <ConfigurationList Condition="  '@(ConfigurationList)' == '' " Include="Debug" />
        <PlatformList Condition="  '@(PlatformList)' == '' and $(Platform) != '' " Include="$(Platform.Split(';'))" />
        <PlatformList Condition="  '@(PlatformList)' == '' " Include="Windows"  />
    </ItemGroup>
    <ItemGroup>
        <Solution Include="*.sln" />
    </ItemGroup>
    <Target Name="Build" Outputs="%(PlatformList.Identity)">
        <PropertyGroup>
            <CurrentPlatform>%(PlatformList.Identity)</CurrentPlatform>
        </PropertyGroup>
        <MSBuild Projects="@(Solution)"
                 BuildInParallel="true"
                 Targets="Build"
                 Properties="Configuration=%(ConfigurationList.Identity);Platform=$(CurrentPlatform);AllowUnsafeBlocks=true" />
    </Target>
</Project>