error in build script on Ubuntu 16.04

[SimonEnsemble]

INFO: Building YT
=================================[ ERROR: YT ]==================================

LoadError: UndefVarError: @windows not defined
while loading /home/simoncor/.julia/v0.6/YT/deps/build.jl, in expression starting on line 4

================================================================================

================================[ BUILD ERRORS ]================================

WARNING: YT had build errors.

 - packages with build errors remain installed in /home/simoncor/.julia/v0.6
 - build the package(s) and all dependencies with `Pkg.build("YT")`
 - build a single package by running its `deps/build.jl` script

================================================================================

Julia v0.6.3

[pnavaro]

same issue on macOS High Sierra with Julia v0.6.4