Pads the prerelease part exported to TeamCity by GitVersion and exports a new version to enforce NuGet v2 compatibility in dnx projects

PadGitVersionPrereleasePartForDnxBuildVersion.ps1

$VersionEnvironmentVariable = "BUILD_NUMBER"
$DnxVersionEnvironmentVariable = "DNX_BUILD_VERSION"

if (Test-Path Env:$VersionEnvironmentVariable) {
    $BuildNumber = [Environment]::GetEnvironmentVariable($VersionEnvironmentVariable)

    if ($BuildNumber -match '^(?<Version>\d+\.\d+\.\d+)-(?<PrereleaseTag>\w+)\.(?<PrereleaseBuild>\d+)')
    {
        $Version = $Matches["Version"]
        $Tag = $Matches["PrereleaseTag"]
        $Build = ([int]$Matches["PrereleaseBuild"]).ToString("000000")

        $NewBuildNumber = $Version+"-"+$Tag+$Build
        Write-Host Rewriting Version $BuildNumber to $NewBuildNumber

        Write-Host "##teamcity[setParameter name='env.$VersionEnvironmentVariable' value='$NewBuildNumber']"
        Write-Host "##teamcity[setParameter name='env.$DnxVersionEnvironmentVariable' value='$Tag$Build']"
    }
    else {
        Write-Host $VersionEnvironmentVariable ist kein Prerelease, ignoriere Schritt.
    }
}
else {
    Write-Host $VersionEnvironmentVariable nicht gesetzt, ignoriere Schritt.
}