* lib/quote.h, lib/quote.c, lib/quotearg.h, lib/quotearg.c:

* m4/prereq.m4, m4/c-bs-a.m4, m4/mbstate.m4:
New files, from Fileutils 4.0.27.
* src/main.c (printable_version): Remove.
* src/lex.c, src/reader.c: Use `quote'.


* lib/error.c, lib/error.h: New files, needed by xmalloc.c.

m4/c-bs-a.m4

@@ -0,0 +1,23 @@
+#serial 3
+
+dnl From Paul Eggert.
+
+AC_DEFUN(AC_C_BACKSLASH_A,
+[
+  AC_CACHE_CHECK([whether backslash-a works in strings], ac_cv_c_backslash_a,
+   [AC_TRY_COMPILE([],
+     [
+#if '\a' == 'a'
+      syntax error;
+#endif
+      char buf['\a' == 'a' ? -1 : 1];
+      buf[0] = '\a';
+      return buf[0] != "\a"[0];
+     ],
+     ac_cv_c_backslash_a=yes,
+     ac_cv_c_backslash_a=no)])
+  if test $ac_cv_c_backslash_a = yes; then
+    AC_DEFINE(HAVE_C_BACKSLASH_A, 1,
+      [Define if backslash-a works in C strings.])
+  fi
+])