* lib/xstrndup.c, lib/strchr.c:
New, stolen from the Fileutils 4.1.
* lib/Makefile.am (libbison_a_SOURCES): Adjust.
* configure.in: Check for the presence of memrchr, strchr,
strnlen, and of their prototypes.
Don't check for strndup: we no longer use it.
* src/system.h: Adjust the prototypes.
* lib/quotearg.c: BSD/OS 4.1 wchar.h requires FILE and struct
tm to be declared.
(HAVE_MBSINIT): Undef if !HAVE_MBRTOWC.
(mbsinit): Define to 1 if !defined mbsinit && !HAVE_MBSINIT.
* m4/Makefile.am (EXTRA_DIST): Add mbrtowc.m4.
* m4/mbrtowc.m4: New file.
* m4/prereq.m4 (jm_PREREQ_QUOTEARG): Check for mbsinit and stddef.h.
Use jm_FUNC_MBRTOWC instead of AC_CHECK_FUNCS(mbrtowc).
New, from fileutils 4.0.37.
* configure.in: Require Autoconf 2.49c. I took some time before
making this decision. This is the only way out for portability
issues in Bison, it would mean way too much duplicate effort to
import in Bison features implemented in 2.49c since 2.13.
AC_REPLACE_FUNCS and AC_CHECK_DECLS the functions above.
