GHC head Solaris bot failing with HsColour needed but wasn't found.

Hello, I've noticed that my GHC head solaris bot is failing with HsColour needed but wasn't found. Set HSCOLOUR_SRCS=NO if you don't want to use it message on stage1 build since Jan 04. Please let me know what I need to install in order to make head build able again. Thanks, Karel