for mips64 to build this with MLIBDIR set to o32
- make mips64 ldd call elf32_compat_ldd as well
- make mips64 elf64 set MLIBDIR to 64
- don't need ld.elf_so's Makefile.ld32 files anymore (they are going away
soon anyway)
tested on amd64 and sparc64, and an earlier version tested on mips64.