[PATCH] Fix the damage done by my other patch from yesterday to strlenopt-49.c

[Joseph Myers]

On Mon, 30 Jul 2018, Bernd Edlinger wrote:

> In the moment I would already be happy if all STRING_CSTs would
> be zero terminated.

generic.texi says they need not be.  Making the STRING_CST contain only 
the bytes of the initializer and not the trailing NUL in the C case where 
the trailing NUL does not fit in the object initialized would of course 
mean you get non-NUL-terminated STRING_CSTs for valid C code as well.

-- 
Joseph S. Myers
joseph@codesourcery.com