http://mirror.sh-linux.org/rpm-2003/SRPMS/gcc-3.2.3-3.src.rpm contains the following patches:

gcc-20030210-sh-linux-1.patch
gcc-3.2.3-libffi-1.patch
gcc-3.2.3-sh-linux-dwarf2-1.patch (*not* applied by the spec file, it's in there by accident)

gcc-3.2.3-libffi-1.patch was needed just to build, I think.

After that was applied, sh4 gcc seemed to compile fine, but c++ programs
failed to execute because libstdc++.so.5 was built without version
info.  This was caused directly by libstdc++-v3/configure setting
SYMVER_MAP=config/linker-map.dummy because it sees that 
no libgcc_s.so was generated; configure says
  checking for shared libgcc... no.

Applying gcc-20030210-sh-linux-1.patch in hopes it makes those problems go away.