Conditionally build Post-Deploy in SSDT SQLPROJ - msbuild

Question

I want to conditionally build the post-deploy script in my SSDT project, but i don't understand how to do that. So normally the post-deploy script is built, but I want a way to NOT build or run the post-deploy script when doing a Debug build. I am running the build from the command-line, so i could pass in properties, but how could i use a property to not run the post-deploy script?
The options i see are SQLCMD, or editing the SQLPROJ file, or passing in properties, but I can't find any reference for what the available properties are and what not for SQLPROJ files.
The file i want to conditionally build is located here:
<ItemGroup>
<PostDeploy Include="PostDeploymentScripts\Script.PostDeployment1.sql" />
</ItemGroup>
My Debug build block looks like this:
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
<OutputPath>bin\Debug\</OutputPath>
<BuildScriptName>$(MSBuildProjectName).sql</BuildScriptName>
<TreatWarningsAsErrors>false</TreatWarningsAsErrors>
<DebugSymbols>true</DebugSymbols>
<DebugType>full</DebugType>
<Optimize>false</Optimize>
<DefineDebug>true</DefineDebug>
<DefineTrace>true</DefineTrace>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
</PropertyGroup>
And my command-line looks like this:
msbuild $sqlprojFilePath /p:Configuration="Debug"

Answer 1

In your .sqlproj, add this line to occur after the import on Microsoft.Data.Tools.Schema.SqlTasks.targets
Find this line in your project file after the import on *SqlTasks.targets.
<Import Project="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v$(MSBuildToolsVersion)\SSDT\Microsoft.Data.Tools.Schema.SqlTasks.targets" />
<PropertyGroup Condition="'$(Configuration)'=='debug'">
<DeployDependsOn />
<SqlDeployDependsOn />
</PropertyGroup>
This removes the deployment projects from the dependency chain and can be modified to use an alternate property.
<PropertyGroup Condition="'$(SkipDeployment)'=='true'">
<DeployDependsOn />
<SqlDeployDependsOn />
</PropertyGroup>
Command line:
msbuild.exe mydb.sqlproj /p:SkipDeployment=true
Big Edit:
Or you can take this:
<ItemGroup>
<PostDeploy Include="PostDeploymentScripts\Script.PostDeployment1.sql" />
</ItemGroup>
and change it to read like so:
<ItemGroup Condition="'$(Configuration)'=='debug'">
<PostDeploy Include="PostDeploymentScripts\Script.PostDeployment1.sql" />
</ItemGroup>

Answer 2

You can do this with a SQLCMD variable. Set one up in the project and check the value of that variable when publishing the project. I blogged about something like this here:
http://schottsql.blogspot.com/2013/05/trick-to-not-run-prepost-sql-on-publish.html
Not sure about the msbuild command-line as I've normally used sqlpackage.exe to push the changes.