Shellology: ksh93 from OpenIndiana ${1+"$@"}

[Pavel Raiskup]

Bob sent me a bug report that libtool's testsuite is currently broken on Open
Indiana, this the underlying problem:

  $ cat test.sh 
  #! /bin/sh

  f ()
  {
     echo "arguments: $#"
  }

  f ${1+"$@"}
  $ ./test.sh a
  arguments: 1
  $ ./test.sh a b
  arguments: 2
  $ ./test.sh a b ""
  arguments: 2
  $ ./test.sh a b "" ""
  arguments: 3
  $ ./test.sh a b "" "" d
  arguments: 5
  $ ./test.sh a b "" "" d ""
  arguments: 5
  $ ./test.sh a b "" "" d "" ""
  arguments: 6
  $ /bin/sh --version
    version         sh (AT&T Research) 93t+ 2010-03-05

The latest *empty* argument is eaten by ${1+"$@"} construct, and I don't
see any work-around (e.g. simlar to what we have for older zsh).  The "$@"
works fine there..

I'm not sure here.  Is this issue worth documenting in Shellology section
withing autoconf.info?  This probably should be fixed somehow in libtool,
but I'm not yet sure what is the proper way.

Pavel