Files excluded from compositing are (from makepanda):
dtool/src/dtoolbase/indent.cxx
panda/src/display/graphicsStateGuardian.cxx
panda/src/dxgsg9/dxGraphicsStateGuardian9.cxx
panda/src/grutil/multitexReducer.cxx
panda/src/pgraph/nodePath.cxx
panda/src/pnmimage/convert_srgb_sse2.cxx (due to being compiled w/ SSE2)