with the syscall numbers changed.
Since 4.4BSD vfork(2) did not share address space, Ovfork.S could be changed
to be identical to fork.S (modulo syscall numbers). __vfork14.S, however,
needs to remain separate since with a shared address space, the stub needs to
pre-decrement the stack and do an indirect jump to the return address, so that
the shared stackframe is still there when the parent returns. (Obviously,
this does not apply to systems which to not build stackframes on leaf calls.)
for the address of a variable used to store the error number instead
of writing to the global errno.
In a multi-threaded program, __errno() will return a pointer to a
thread-specific variable.
thorpej