[PATCH] argp: do not call _IO_fwide() if _LIBC is not defined

[Joseph Myers]

On Wed, 28 Nov 2018, Charles-Antoine Couret wrote:

> _IO_fwide() is defined in libio.h file. This file is included only
> when _LIBC is defined.
> 
> So, in case of compilation of these files without _LIBC definition,
> the compilation failed due to this unknown function.

To confirm: is this (as it looks like) a change that is bringing in some 
conditionals from gnulib, in exactly the form in which they appear in the 
gnulib version of this code, and are there other differences between the 
two versions that would also be desirable to merge?  (The gnulib version 
is the one that is expected to be portable for use outside of glibc.  
Ideally the glibc and gnulib versions of shared code would be identical.)

-- 
Joseph S. Myers
joseph@codesourcery.com