* handle interpreters with nonzero virtual address of entry-point:
subtract p_vaddr from computed entrypoint, as the mips elf exec did.
* Add #ifdef ELF_INTERP_NON_RELOCATABLE/#endif around the code
that tries to choose a `good' address at which to load an interpreter,
if none was set by the emul probe function.
(the address chosen could be improved to avoid fragmenting the
process virtual address space).
* define ELF_INTERP_NON_RELOCATABLE in machine/elf_machdep.h for mips CPUs,
which currently use a GNU-derived ld.so.
ELF_INTERP_NON_RELOCATABLE is not necessary for native NetBSD/alpha ELF
binaries. It may be required for GNU-derived ELF dynamic loaders (Linux/i386?)
macros to use to remove #ifdefs from the machine ID case check.
Eventually, these headers will contain other information, e.g.
machine-dependent relocation information, etc.
