libiberty requirements and ISO C90

[Gabriel Dos Reis]

Ian Lance Taylor <ian@airs.com> writes:

[...]

| I think the more conservative approach would be to simply add strerror
| to AC_CHECK_DECLS, include <string.h> in xstrerror.c (protected by
| HAVE_STRING_H), and protect the strerror declaration with
|     #if !HAVE_DECL_STRERROR

Thanks, that indeed makes sense.  Patch pending.
-- Gaby