Etherboot 5.4.0 seems to compile with gcc-3.4.3 if, in addition to the config changes spelled out on the Wiki, you also comment out PXE support in src/Config:
# Etherboot as a PXE network protocol ROM #CFLAGS+= -DPXE_IMAGE -DPXE_EXPORT
Seems to run, but I haven't reached a point where I can boot something over the network yet.
Steve www.digidescorp.com