gnulib: update, and use the attribute module

* gnulib: Update.
* bootstrap.conf: Use attribute.
* src/system.h: Remove macros for attributes.
Adjust dependencies.
* src/scan-gram.l (DEPRECATED): Rename as...
(DEPRECATED_DIRECTIVE): this, to avoid the clash with the DEPRECATED macro.

src/complain.h

@@ -132,7 +132,7 @@ bool warning_is_enabled (warnings flags);
 
 /** Make a complaint, with maybe a location.  */
 void complain (location const *loc, warnings flags, char const *message, ...)
-  __attribute__ ((__format__ (__printf__, 3, 4)));
+  ATTRIBUTE_FORMAT ((__printf__, 3, 4));
 
 /** Likewise, but with an \a argc/argv interface.  */
 void complain_args (location const *loc, warnings w,
@@ -141,7 +141,7 @@ void complain_args (location const *loc, warnings w,
 /** Make a subcomplain with location and note.  */
 void subcomplain (location const *loc, warnings flags,
                   char const *message, ...)
-  __attribute__ ((__format__ (__printf__, 3, 4)));
+  ATTRIBUTE_FORMAT ((__printf__, 3, 4));
 
 
 /** GNU Bison extension not valid with POSIX Yacc.  */

src/getargs.c

@@ -30,6 +30,7 @@
 #include <getopt.h>
 #include <progname.h>
 #include <quote.h>
+#include <stdnoreturn.h>
 #include <textstyle.h>
 
 #include "complain.h"
@@ -151,8 +152,8 @@ flags_argmatch (const char *opt,
  */
 #define FLAGS_ARGMATCH(FlagName, Args, All)                             \
   flags_argmatch ("--" #FlagName,                                       \
-                  (xargmatch_fn*) argmatch_## FlagName ## _value,        \
-                  argmatch_## FlagName ## _usage,                       \
+                  (xargmatch_fn*) argmatch_## FlagName ## _value,       \
+                  argmatch_ ## FlagName ## _usage,                      \
                   All, &FlagName ## _flag, Args)
 
 /*---------------------.
@@ -337,7 +338,8 @@ const argmatch_feature_group_type argmatch_feature_group =
 | Display the help message and exit STATUS.  |
 `-------------------------------------------*/
 
-static void usage (int) ATTRIBUTE_NORETURN;
+ _Noreturn
+static void usage (int);
 
 static void
 usage (int status)
@@ -860,7 +862,7 @@ getargs (int argc, char *argv[])
 void
 tr (char *s, char from, char to)
 {
-  for (; *s; s++)
+  for (; *s; ++s)
     if (*s == from)
       *s = to;
 }

src/scan-gram.l

@@ -74,7 +74,7 @@ static boundary scanner_cursor;
     yyless (0);                                                 \
   } while (0)
 
-#define DEPRECATED(Msg)                                         \
+#define DEPRECATED_DIRECTIVE(Msg)                               \
   do {                                                          \
     deprecated_directive (loc, yytext, Msg);                    \
     scanner_cursor.column -= mbsnwidth (Msg, strlen (Msg), 0);  \
@@ -295,15 +295,15 @@ eqopt    ({sp}=)?
   "%name"[-_]"prefix"{eqopt}{sp}    RETURN_VALUE (PERCENT_NAME_PREFIX, uniqstr_new (yytext));
 
   /* Deprecated since Bison 2.7.90, 2012. */
-  "%default"[-_]"prec"              DEPRECATED ("%default-prec");
+  "%default"[-_]"prec"              DEPRECATED_DIRECTIVE ("%default-prec");
   "%error"[-_]"verbose"             RETURN_VALUE (PERCENT_ERROR_VERBOSE, uniqstr_new (yytext));
-  "%expect"[-_]"rr"                 DEPRECATED ("%expect-rr");
+  "%expect"[-_]"rr"                 DEPRECATED_DIRECTIVE ("%expect-rr");
   "%file-prefix"{eqopt}             RETURN_VALUE (PERCENT_FILE_PREFIX, uniqstr_new (yytext));
-  "%fixed"[-_]"output"[-_]"files"   DEPRECATED ("%output \"y.tab.c\"");
-  "%no"[-_]"default"[-_]"prec"      DEPRECATED ("%no-default-prec");
-  "%no"[-_]"lines"                  DEPRECATED ("%no-lines");
-  "%output"{eqopt}                  DEPRECATED ("%output");
-  "%token"[-_]"table"               DEPRECATED ("%token-table");
+  "%fixed"[-_]"output"[-_]"files"   DEPRECATED_DIRECTIVE ("%output \"y.tab.c\"");
+  "%no"[-_]"default"[-_]"prec"      DEPRECATED_DIRECTIVE ("%no-default-prec");
+  "%no"[-_]"lines"                  DEPRECATED_DIRECTIVE ("%no-lines");
+  "%output"{eqopt}                  DEPRECATED_DIRECTIVE ("%output");
+  "%token"[-_]"table"               DEPRECATED_DIRECTIVE ("%token-table");
 
   "%"{id} {
     complain (loc, complaint, _("invalid directive: %s"), quote (yytext));

src/system.h

@@ -110,28 +110,7 @@ typedef size_t uintptr_t;
    Bison's performance anyway.  */
 # define PACIFY_CC(Code) Code
 
-# ifndef __attribute__
-/* This feature is available in gcc versions 2.5 and later.  */
-#  if (! defined __GNUC__ || __GNUC__ < 2 \
-       || (__GNUC__ == 2 && __GNUC_MINOR__ < 5))
-#   define __attribute__(Spec) /* empty */
-#  endif
-# endif
-
-/* The __-protected variants of 'format' and 'printf' attributes
-   are accepted by gcc versions 2.6.4 (effectively 2.7) and later.  */
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7)
-#  define __format__ format
-#  define __printf__ printf
-# endif
-
-# ifndef ATTRIBUTE_NORETURN
-#  define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
-# endif
-
-# ifndef ATTRIBUTE_UNUSED
-#  define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
-# endif
+# include <attribute.h>
 
 
 /*------.

src/uniqstr.c

@@ -21,6 +21,7 @@
 #include <config.h>
 #include "system.h"
 
+#include <attribute.h>
 #include <error.h>
 #include <hash.h>
 #include <quotearg.h>
@@ -117,12 +118,11 @@ uniqstr_print (uniqstr ustr)
 }
 
 static bool
-uniqstr_print_processor (void *ustr, void *null ATTRIBUTE_UNUSED)
+uniqstr_print_processor (void *ustr, void *null MAYBE_UNUSED)
 {
   return uniqstr_print (ustr);
 }
 
-
 int
 uniqstr_cmp (uniqstr l, uniqstr r)
 {