Is it possible to use the Code Sourcery ARM 2006q1-6 Symbian OS toolchain to build Symbian 9.1 apps after the MR?

I had tried before the MR and got numerous errors in the SDK header files. I'd really like to move to a gcc 4.x based environment as Symbian is the last non-modern compiler chain I have to use currently (I use gcc 4.x for linux and brew development and msvc 8 for win32, wince, and win64 development).