gnulib: update, and use the attribute module

[Akim Demaille]

commit fb49a10e2cda3e7d9069b0cd8ef0ca0bc44bef9a
Author: Akim Demaille <address@hidden>
Date:   Fri May 8 17:35:23 2020 +0200

    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.

diff --git a/bootstrap.conf b/bootstrap.conf
index a8cb0291..f0207de8 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -17,7 +17,7 @@
 
 # gnulib modules used by this package.
 gnulib_modules='
-  argmatch array-list assert assure
+  argmatch array-list assert assure attribute
   bitsetv
   calloc-posix close closeout config-h c-strcase
   configmake
diff --git a/gnulib b/gnulib
index 2ac33b29..2e3f0c91 160000
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 2ac33b29fc09f72a18eb08829eb142eb86428747
+Subproject commit 2e3f0c910896a52ce0944bd04d4da3413682cf1f
diff --git a/lib/.gitignore b/lib/.gitignore
index 84f80d99..a34e66ae 100644
--- a/lib/.gitignore
+++ b/lib/.gitignore
@@ -18,6 +18,7 @@
 /asnprintf.c
 /asprintf.c
 /assure.h
+/attribute.h
 /basename-lgpl.c
 /basename.c
 /binary-io.c
diff --git a/src/complain.h b/src/complain.h
index 65204ce0..84b2381f 100644
--- a/src/complain.h
+++ b/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.  */
diff --git a/src/getargs.c b/src/getargs.c
index 6f19a4ea..74474704 100644
--- a/src/getargs.c
+++ b/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;
 }
diff --git a/src/scan-gram.l b/src/scan-gram.l
index 80a46134..763432d8 100644
--- a/src/scan-gram.l
+++ b/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));
diff --git a/src/system.h b/src/system.h
index 606d3c46..33986069 100644
--- a/src/system.h
+++ b/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>
 
 
 /*------.
diff --git a/src/uniqstr.c b/src/uniqstr.c
index d16e254a..6dba20a6 100644
--- a/src/uniqstr.c
+++ b/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)
 {