Don't allow undefined global symbols to pass(all archs needs fixing,

Don't allow undefined global symbols to pass(all archs needs fixing,
but powerpc).
If you are using buildroot and soft floating point, you may have to
rebuild the libm.so library, copy it to staging_dir/lib and rebuild
your application.

Move handling of R_386_COPY back into _dl_do_reloc(all archs should
do this). Adjust the first argument to _dl_memcpy as it looks wrong
to have symtab[symtab_index].st_value as destination for the mem copy.