[BUG] 'eval' returns 0 on error

[Ron Yorston]

Martijn Dekker wrote:
>The issue turns out to be more general than that: on an interactive
>shell, or when invoking a script using Busybox 1.26.0 ash, the exit
>status is 0 on a parsing error as well.

And that's not all.  This also gives the wrong result:

   $ rm -f xxx
   $ eval cat <xxx
   $ echo $?
   0

Patch to follow.

Ron