I started looking at it in September. I made a bit of minor progress and laid it aside for other things.
The problem is the approach that was used for the build. SAGE being a collection of apps that are built together means building several projects at one time. This wouldn't be too bad, and in some ways would almost make it easier. However, they tar these files in some format that means I have to try to recreate it, otherwise, all my changes are lost on the next make. Each iteration of make untars each package regardless of any other consideration. It took me awhile to figure out that I can't use the latest tar to work with the package as it didn't handle the piping that was being done.
Now that GCC 4.3.3 is available, it may make it somewhat easier as I seem to recall having to do some work to get around having an "older" compiler.
The readme says:
Sage builds with GCC >= 3.x and GCC >= 4.1.x
http://www.sagemath.org/doc/inst/node5.html says it has to be at least 3.4.x
it also says that 4.3.0 does not yet work.