I tried to find out that gd means in boost library name and I only found two other people looking for the same thing.
I suppose it should be a place where this is clearly documented and I would like to find it.
mt- multitheaded, get it withbjam threading=multis-bjam runtime-link=staticg- using debug versions of the standard and runtime support libraries. what bjam switch???d- debugbjam variant=debug
Update
How do I control what bjam switches controls the above variants? In fact the only one that I wasn't able to identify is the g.