do not test --version
do not test --version

`llvm-strip-7` is a sane valid strip command that LLVM 7 ships, albeit
it does not understand `--version`.  It is a bad idea to check that
option.  Instead just see if the command actually strips something.  A
copy of `/bin/sh` should suffice.  That file must be ubiquitous.

nobu/rubyspec,eregon/rubyspec,eregon/rubyspec,ruby/spec,nobu/rubyspec,eregon/rubyspec,ruby/spec,nobu/rubyspec,ruby/spec