Changing colors doesn't work in Glulx as it's supposed to according to the DM4
This comes from auraes at https://intfiction.org/t/inform-library-6-12-and-inform-6-33-1-for-unix-go-beta/7207/8
On page 311 in the DM4, one of the colors available is "current colour". This has been missing from the Library since at least 6/1. This causes the SetColour() function to not work similarly to the @set_colour opcode.
Even if the program supplies this constant, the SetColour() function thwarts the correct functionality by enclosing the entire body of the function in an if statement that causes the function to do nothing if foreground and background are not both supplied.
Report originally filed at http://inform7.com/mantis/view.php?id=1377