* move all exec-type specific information from struct emul to execsw[] and
provide single struct emul per emulation
* elf:
- kern/exec_elf32.c:probe_funcs[] is gone, execsw[] how has one entry
per emulation and contains pointer to respective probe function
- interp is allocated via MALLOC() rather than on stack
- elf_args structure is allocated via MALLOC() rather than malloc()
* ecoff: the per-emulation hooks moved from alpha and mips specific code
to OSF1 and Ultrix compat code as appropriate, execsw[] has one entry per
emulation supporting ecoff with appropriate probe function
* the makecmds/probe functions don't set emulation, pointer to emulation is
part of appropriate execsw[] entry
* constify couple of structures
* add arguments describing the vnode and ecoff header of the executable
being set up to the [onz]magic setup functions.
* export the stack setup function and the [onz]magic setup functions.
* call the MD ecoff hook _before_ the [onz]magic and stack setup
functions, and bail out early if the MD hook sets up vmcmds.
jdolecek