converters/libiconv breakage with new glibc

[Blair Sadewitz <blair.sadewitz%gmail.com@localhost>]

Just a "heads up":

This is the relevant log entry from gnulib git:

I'm not sure how many people are using pkgsrc with a pkgsrc-provided libiconv where this would matter, but in that case the build fails.

commit 66712c23388e93e5c518ebc8515140fa0c807348

Author: Eric Blake <eblake%redhat.com@localhost>

Date:   Thu Mar 29 13:30:41 2012 -0600

    stdio: don't assume gets any more

    

    Gnulib intentionally does not have a gets module, and now that C11

    and glibc have dropped it, we should be more proactive about warning

    any user on a platform that still has a declaration of this dangerous

    interface.

    

    * m4/stdio_h.m4 (gl_STDIO_H, gl_STDIO_H_DEFAULTS): Drop gets

    support.

    * modules/stdio (Makefile.am): Likewise.

    * lib/stdio-read.c (gets): Likewise.

    * tests/test-stdio-c++.cc: Likewise.

    * m4/warn-on-use.m4 (gl_WARN_ON_USE_PREPARE): Fix comment.

    * lib/stdio.in.h (gets): Make warning occur in more places.

    * doc/posix-functions/gets.texi (gets): Update documentation.

    Reported by Christer Solskogen.

    

    Signed-off-by: Eric Blake <eblake%redhat.com@localhost>