fix eval quoting: double-quote variable expansions. (was: [bug-libunistring] Fix quoting in exported.sh.in, allow multiple arguments.)

[Ralf Wildenhues]

Hi Bruno,

* Bruno Haible wrote on Sat, May 02, 2009 at 11:57:41AM CEST:
> Ralf Wildenhues wrote:
> > A better fix will require a better AC_TRY_EVAL replacement from
> > Autoconf.
> 
> How could the expansion of AC_TRY_EVAL be changed, while preserving
> backward compatibility?

It can't.  But there is a need for a better replacement, with a
different name, to which we can move once that has been implemented
and propagated sufficiently.

> >     Fix quoting of eval'ed variable.
> >     
> >     * libltdl/m4/libtool.m4 (_LT_CMD_GLOBAL_SYMBOLS): Double-quote
> >     $lt_cv_sys_global_symbol_pipe for eval, like we do in ltmain,
> >     in order to preserve TABs and multiple adjacent whitespace.
> >     Report by Bruno Haible.
> 
> There are 5 more occurrences of this idiom, IMO, at lines 4127, 4142,
> 4145, 4158, 4288, but I'm not sure whether the way they are eval'ed
> in ltmain.m4sh:6739 makes it a non-issue.

Ouch.  Thanks for checking this.  We fixed func_show_eval, but forgot
this similar code piece.

I'm working on an audit of 'eval' uses within Libtool.  The patch will
be bigger.

Cheers, and thanks again,
Ralf