Fix build on .NET 1.x.
Fix build on .NET 1.x.

dahmage/nantcontrib,nant/nantcontrib,dahmage/nantcontrib,cgourlay/nantcontrib,rmboggs/nantcontrib,cgourlay/nantcontrib,dahmage/nantcontrib,nant/nantcontrib,rmboggs/nantcontrib,rmboggs/nantcontrib,nant/nantcontrib,cgourlay/nantcontrib