cudaPackages: fix multiplex builder isSupported check

  # computeName :: Package -> String

  computeName = {version, ...}: mkVersionedPackageName pname version;

  # Check whether a package supports our CUDA version

  # Check whether a package supports our CUDA version and platform.

  # isSupported :: Package -> Bool

  isSupported =

    package:

    !(strings.hasPrefix "unsupported" package.platform)

    # The `platform` attribute of the package is NVIDIA's name for a redistributable architecture.

    redistArch == package.platform

    && strings.versionAtLeast cudaVersion package.minCudaVersion

    && strings.versionAtLeast package.maxCudaVersion cudaVersion;