build fails in compat ld.elf_so install

[Arto Huusko <arto.huusko%pp2.inet.fi@localhost>]

Hi,

distribution build fails currently on amd64 because compat
ld.elf_so is not built. install fails, when ld.elf_so-i386
is not found. obj directory has .d files but no .o nor the
binary.

Building with rev 1.4 of compat/libexec/ld.elf_so/Makefile
fixes things.