OK, I've done something horribly wrong. The latest patch fails to build libgcc. The initial problem was reported by TheMole on AtariAge. I just got too confident and didn't test with a full build.

I was able to replicate this depressingly easily. The problem is that the offending line declares a function prototype which uses the FILE macro from stdio.h, but does not include that header file. This apparently is not a problem when compiling GCC, but libgcc is not so forgiving. It turns out that the problem prototype is not really needed there, so we can comment that out and get a bit farther.

Until we hit the next problem:

insn does not satisfy its constraints:
(insn 229 40 238 7 ../../../libgcc/../gcc/unwind-dw2-fde.c:612 (set:QI (reg:QI 27)
        (subreg:QI (reg:HI 27) 1)) 73 {movqi} (nil))
../../../libgcc/../gcc/unwind-dw2-fde.c: In function ‘classify_object_over_fdes’:
../../../libgcc/../gcc/unwind-dw2-fde.c:645: internal compiler error: in reload_cse_simplify_operands, at postreload.c:396
Please submit a full bug report,
with preprocessed source if appropriate.
See for instructions.
make[1]: *** [unwind-dw2-fde.o] Error 1
make[1]: Leaving directory `/home/eric/dev/tios/src/gcc_installer/temp/build/gcc-4.4.0/build/tms9900/libgcc'

Somehow the stupid byte conversion stuff got back in there. Grr.