Update contrib/libs/libidn to 1.42

1 files changed, 359 insertions, 139 deletions

diff --git a/contrib/libs/libidn/config-linux.h b/contrib/libs/libidn/config-linux.h
index 78173951d6..3bc2edae03 100644
--- a/contrib/libs/libidn/config-linux.h
+++ b/contrib/libs/libidn/config-linux.h
@@ -1,6 +1,10 @@
 /* config.h.  Generated from config.h.in by configure.  */
 /* config.h.in.  Generated from configure.ac by autoheader.  */
 
+/* Witness that <config.h> has been included.  */
+#define _GL_CONFIG_H_INCLUDED 1
+
+
 /* Define to the number of bits in type 'ptrdiff_t'. */
 /* #undef BITSIZEOF_PTRDIFF_T */
 
@@ -115,6 +119,9 @@
 /* Define to 1 when the gnulib module getopt-posix should be tested. */
 #define GNULIB_TEST_GETOPT_POSIX 1
 
+/* Define to 1 when the gnulib module getprogname should be tested. */
+#define GNULIB_TEST_GETPROGNAME 1
+
 /* Define to 1 when the gnulib module open should be tested. */
 #define GNULIB_TEST_OPEN 1
 
@@ -174,6 +181,12 @@
 /* Define to 1 if you have the <crtdefs.h> header file. */
 /* #undef HAVE_CRTDEFS_H */
 
+/* Define to 1 if bool, true and false work as per C2023. */
+/* #undef HAVE_C_BOOL */
+
+/* Define to 1 if the static_assert keyword works. */
+/* #undef HAVE_C_STATIC_ASSERT */
+
 /* Define to 1 if C supports variable-length arrays. */
 #define HAVE_C_VARARRAYS 1
 
@@ -217,6 +230,10 @@
    don't. */
 #define HAVE_DECL_GETLINE 1
 
+/* Define to 1 if you have the declaration of `getw', and to 0 if you don't.
+   */
+#define HAVE_DECL_GETW 1
+
 /* Define to 1 if you have the declaration of `program_invocation_name', and
    to 0 if you don't. */
 #define HAVE_DECL_PROGRAM_INVOCATION_NAME 1
@@ -225,6 +242,10 @@
    and to 0 if you don't. */
 #define HAVE_DECL_PROGRAM_INVOCATION_SHORT_NAME 1
 
+/* Define to 1 if you have the declaration of `putw', and to 0 if you don't.
+   */
+#define HAVE_DECL_PUTW 1
+
 /* Define to 1 if you have the declaration of `strerror_r', and to 0 if you
    don't. */
 #define HAVE_DECL_STRERROR_R 1
@@ -240,6 +261,12 @@
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #define HAVE_DLFCN_H 1
 
+/* Define to 1 if you have the `error' function. */
+#define HAVE_ERROR 1
+
+/* Define to 1 if you have the <error.h> header file. */
+#define HAVE_ERROR_H 1
+
 /* Define to 1 if you have the `fcntl' function. */
 #define HAVE_FCNTL 1
 
@@ -264,6 +291,9 @@
 /* Define to 1 if you have the `getexecname' function. */
 /* #undef HAVE_GETEXECNAME */
 
+/* Define to 1 if you have the `getline' function. */
+#define HAVE_GETLINE 1
+
 /* Define to 1 if you have the <getopt.h> header file. */
 #define HAVE_GETOPT_H 1
 
@@ -327,6 +357,12 @@
 /* Define to 1 if 'wint_t' is a signed integer type. */
 /* #undef HAVE_SIGNED_WINT_T */
 
+/* Define to 1 if you have the <stdbool.h> header file. */
+#define HAVE_STDBOOL_H 1
+
+/* Define to 1 if you have the <stdckdint.h> header file. */
+/* #undef HAVE_STDCKDINT_H */
+
 /* Define to 1 if you have the <stdint.h> header file. */
 #define HAVE_STDINT_H 1
 
@@ -399,6 +435,9 @@
 /* Define to 1 if you have the <unistd.h> header file. */
 #define HAVE_UNISTD_H 1
 
+/* Define to 1 if you have the <unistring/woe32dll.h> header file. */
+/* #undef HAVE_UNISTRING_WOE32DLL_H */
+
 /* Define to 1 if the system has the type 'unsigned long long int'. */
 #define HAVE_UNSIGNED_LONG_LONG_INT 1
 
@@ -427,9 +466,6 @@
 /* Define to 1 if O_NOFOLLOW works. */
 #define HAVE_WORKING_O_NOFOLLOW 1
 
-/* Define to 1 if the system has the type `_Bool'. */
-#define HAVE__BOOL 1
-
 /* Define to 1 if you have the `_set_invalid_parameter_handler' function. */
 /* #undef HAVE__SET_INVALID_PARAMETER_HANDLER */
 
@@ -492,7 +528,8 @@
 # define _GL_EXTERN_INLINE_STDHEADER_BUG
 #endif
 #if ((__GNUC__ \
-      ? defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__ \
+      ? (defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__ \
+         && !defined __PCC__) \
       : (199901L <= __STDC_VERSION__ \
          && !defined __HP_cc \
          && !defined __PGI \
@@ -502,6 +539,7 @@
 # define _GL_EXTERN_INLINE extern inline
 # define _GL_EXTERN_INLINE_IN_USE
 #elif (2 < __GNUC__ + (7 <= __GNUC_MINOR__) && !defined __STRICT_ANSI__ \
+       && !defined __PCC__ \
        && !defined _GL_EXTERN_INLINE_STDHEADER_BUG)
 # if defined __GNUC_GNU_INLINE__ && __GNUC_GNU_INLINE__
    /* __gnu_inline__ suppresses a GCC 4.2 diagnostic.  */
@@ -563,6 +601,9 @@
 #endif
 
 
+/* Define to 1 on musl libc. */
+/* #undef MUSL_LIBC */
+
 /* Define to 1 if open() fails to recognize a trailing slash. */
 /* #undef OPEN_TRAILING_SLASH_BUG */
 
@@ -585,7 +626,7 @@
 /* #undef PACKAGE_PACKAGER_VERSION */
 
 /* Define to the full name and version of this package. */
-#define PACKAGE_STRING "GNU Libidn 1.41"
+#define PACKAGE_STRING "GNU Libidn 1.42"
 
 /* Define to the one symbol short name of this package. */
 #define PACKAGE_TARNAME "libidn"
@@ -594,7 +635,7 @@
 #define PACKAGE_URL "https://www.gnu.org/software/libidn/"
 
 /* Define to the version of this package. */
-#define PACKAGE_VERSION "1.41"
+#define PACKAGE_VERSION "1.42"
 
 /* Define to the type that is the result of default argument promotions of
    type mode_t. */
@@ -703,11 +744,15 @@
 #ifndef __STDC_WANT_IEC_60559_DFP_EXT__
 # define __STDC_WANT_IEC_60559_DFP_EXT__ 1
 #endif
+/* Enable extensions specified by C23 Annex F.  */
+#ifndef __STDC_WANT_IEC_60559_EXT__
+# define __STDC_WANT_IEC_60559_EXT__ 1
+#endif
 /* Enable extensions specified by ISO/IEC TS 18661-4:2015.  */
 #ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__
 # define __STDC_WANT_IEC_60559_FUNCS_EXT__ 1
 #endif
-/* Enable extensions specified by ISO/IEC TS 18661-3:2015.  */
+/* Enable extensions specified by C23 Annex H and ISO/IEC TS 18661-3:2015.  */
 #ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
 # define __STDC_WANT_IEC_60559_TYPES_EXT__ 1
 #endif
@@ -731,7 +776,7 @@
 
 
 /* Version number of package */
-#define VERSION "1.41"
+#define VERSION "1.42"
 
 /* Define to l, ll, u, ul, ull, etc., as suitable for constants of type
    'wchar_t'. */
@@ -759,7 +804,7 @@
 /* Define to enable the declarations of ISO C 11 types and functions. */
 /* #undef _ISOC11_SOURCE */
 
-/* Define for large files, on AIX-style hosts. */
+/* Define to 1 on platforms where this makes off_t a 64-bit type. */
 /* #undef _LARGE_FILES */
 
 /* The _Noreturn keyword of C11.  */
@@ -775,6 +820,11 @@
        AIX system header files and several gnulib header files use precisely
        this syntax with 'extern'.  */
 #  define _Noreturn [[noreturn]]
+# elif (defined __clang__ && __clang_major__ < 16 \
+        && defined _GL_WORK_AROUND_LLVM_BUG_59792)
+   /* Compile with -D_GL_WORK_AROUND_LLVM_BUG_59792 to work around
+      that rare LLVM bug, though you may get many false-alarm warnings.  */
+#  define _Noreturn
 # elif ((!defined __cplusplus || defined __clang__) \
         && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) \
             || (!defined __STRICT_ANSI__ \
@@ -793,7 +843,7 @@
 #endif
 
 
-/* Number of bits in a timestamp, on hosts where this is settable. */
+/* Number of bits in time_t, on hosts where this is settable. */
 /* #undef _TIME_BITS */
 
 /* For standard stat data types on VMS. */
@@ -803,7 +853,7 @@
    used. */
 /* #undef __GETOPT_PREFIX */
 
-/* For 64-bit time_t on 32-bit mingw. */
+/* Define to 1 on platforms where this makes time_t a 64-bit type. */
 /* #undef __MINGW_USE_VC2005_COMPAT */
 
 /* Define to 1 if the system <stdint.h> predates C++11. */
@@ -848,7 +898,7 @@
      && (!defined __clang_minor__ \
          || (defined __apple_build_version__ \
              ? 6000000 <= __apple_build_version__ \
-             : 3 < __clang_major__ + (5 <= __clang_minor__))))
+             : 5 <= __clang_major__)))
 # define _GL_HAS_ATTRIBUTE(attr) __has_attribute (__##attr##__)
 #else
 # define _GL_HAS_ATTRIBUTE(attr) _GL_ATTR_##attr
@@ -882,16 +932,30 @@
 # define _GL_ATTR_warn_unused_result _GL_GNUC_PREREQ (3, 4)
 #endif
 
-#ifdef __has_c_attribute
-# if ((defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) <= 201710 \
-      && _GL_GNUC_PREREQ (4, 6))
-#  pragma GCC diagnostic ignored "-Wpedantic"
-# endif
-# define _GL_HAS_C_ATTRIBUTE(attr) __has_c_attribute (__##attr##__)
+/* Use __has_c_attribute if available.  However, do not use with
+   pre-C23 GCC, which can issue false positives if -Wpedantic.  */
+#if (defined __has_c_attribute \
+     && ! (_GL_GNUC_PREREQ (4, 6) \
+           && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) <= 201710))
+# define _GL_HAVE___HAS_C_ATTRIBUTE 1
 #else
-# define _GL_HAS_C_ATTRIBUTE(attr) 0
+# define _GL_HAVE___HAS_C_ATTRIBUTE 0
 #endif
 
+/* Define if, in a function declaration, the attributes in bracket syntax
+   [[...]] must come before the attributes in __attribute__((...)) syntax.
+   If this is defined, it is best to avoid the bracket syntax, so that the
+   various _GL_ATTRIBUTE_* can be cumulated on the same declaration in any
+   order.  */
+#ifdef __cplusplus
+# if defined __clang__
+#  define _GL_BRACKET_BEFORE_ATTRIBUTE 1
+# endif
+#else
+# if defined __GNUC__ && !defined __clang__
+#  define _GL_BRACKET_BEFORE_ATTRIBUTE 1
+# endif
+#endif
 
 /* _GL_ATTRIBUTE_ALLOC_SIZE ((N)) declares that the Nth argument of the function
    is the size of the returned memory block.
@@ -899,29 +963,35 @@
    by the Nth argument of the function is the size of the returned memory block.
  */
 /* Applies to: function, pointer to function, function types.  */
-#if _GL_HAS_ATTRIBUTE (alloc_size)
-# define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
-#else
-# define _GL_ATTRIBUTE_ALLOC_SIZE(args)
+#ifndef _GL_ATTRIBUTE_ALLOC_SIZE
+# if _GL_HAS_ATTRIBUTE (alloc_size)
+#  define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
+# else
+#  define _GL_ATTRIBUTE_ALLOC_SIZE(args)
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_ALWAYS_INLINE tells that the compiler should always inline the
    function and report an error if it cannot do so.  */
 /* Applies to: function.  */
-#if _GL_HAS_ATTRIBUTE (always_inline)
-# define _GL_ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__))
-#else
-# define _GL_ATTRIBUTE_ALWAYS_INLINE
+#ifndef _GL_ATTRIBUTE_ALWAYS_INLINE
+# if _GL_HAS_ATTRIBUTE (always_inline)
+#  define _GL_ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__))
+# else
+#  define _GL_ATTRIBUTE_ALWAYS_INLINE
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_ARTIFICIAL declares that the function is not important to show
     in stack traces when debugging.  The compiler should omit the function from
     stack traces.  */
 /* Applies to: function.  */
-#if _GL_HAS_ATTRIBUTE (artificial)
-# define _GL_ATTRIBUTE_ARTIFICIAL __attribute__ ((__artificial__))
-#else
-# define _GL_ATTRIBUTE_ARTIFICIAL
+#ifndef _GL_ATTRIBUTE_ARTIFICIAL
+# if _GL_HAS_ATTRIBUTE (artificial)
+#  define _GL_ATTRIBUTE_ARTIFICIAL __attribute__ ((__artificial__))
+# else
+#  define _GL_ATTRIBUTE_ARTIFICIAL
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_COLD declares that the function is rarely executed.  */
@@ -929,14 +999,16 @@
 /* Avoid __attribute__ ((cold)) on MinGW; see thread starting at
    <https://lists.gnu.org/r/emacs-devel/2019-04/msg01152.html>.
    Also, Oracle Studio 12.6 requires 'cold' not '__cold__'.  */
-#if _GL_HAS_ATTRIBUTE (cold) && !defined __MINGW32__
-# ifndef __SUNPRO_C
-#  define _GL_ATTRIBUTE_COLD __attribute__ ((__cold__))
+#ifndef _GL_ATTRIBUTE_COLD
+# if _GL_HAS_ATTRIBUTE (cold) && !defined __MINGW32__
+#  ifndef __SUNPRO_C
+#   define _GL_ATTRIBUTE_COLD __attribute__ ((__cold__))
+#  else
+#   define _GL_ATTRIBUTE_COLD __attribute__ ((cold))
+#  endif
 # else
-#  define _GL_ATTRIBUTE_COLD __attribute__ ((cold))
+#  define _GL_ATTRIBUTE_COLD
 # endif
-#else
-# define _GL_ATTRIBUTE_COLD
 #endif
 
 /* _GL_ATTRIBUTE_CONST declares that it is OK for a compiler to omit duplicate
@@ -946,10 +1018,12 @@
    forever, and does not call longjmp.
    (This attribute is stricter than _GL_ATTRIBUTE_PURE.)  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (const)
-# define _GL_ATTRIBUTE_CONST __attribute__ ((__const__))
-#else
-# define _GL_ATTRIBUTE_CONST
+#ifndef _GL_ATTRIBUTE_CONST
+# if _GL_HAS_ATTRIBUTE (const)
+#  define _GL_ATTRIBUTE_CONST __attribute__ ((__const__))
+# else
+#  define _GL_ATTRIBUTE_CONST
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_DEALLOC (F, I) declares that the function returns pointers
@@ -958,16 +1032,25 @@
    _GL_ATTRIBUTE_DEALLOC_FREE declares that the function returns pointers that
    can be freed via 'free'; it can be used only after declaring 'free'.  */
 /* Applies to: functions.  Cannot be used on inline functions.  */
-#if _GL_GNUC_PREREQ (11, 0)
-# define _GL_ATTRIBUTE_DEALLOC(f, i) __attribute__ ((__malloc__ (f, i)))
-#else
-# define _GL_ATTRIBUTE_DEALLOC(f, i)
+#ifndef _GL_ATTRIBUTE_DEALLOC
+# if _GL_GNUC_PREREQ (11, 0)
+#  define _GL_ATTRIBUTE_DEALLOC(f, i) __attribute__ ((__malloc__ (f, i)))
+# else
+#  define _GL_ATTRIBUTE_DEALLOC(f, i)
+# endif
 #endif
 /* If gnulib's <string.h> or <wchar.h> has already defined this macro, continue
    to use this earlier definition, since <stdlib.h> may not have been included
    yet.  */
 #ifndef _GL_ATTRIBUTE_DEALLOC_FREE
-# define _GL_ATTRIBUTE_DEALLOC_FREE _GL_ATTRIBUTE_DEALLOC (free, 1)
+# if defined __cplusplus && defined __GNUC__ && !defined __clang__
+/* Work around GCC bug <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108231> */
+#  define _GL_ATTRIBUTE_DEALLOC_FREE \
+     _GL_ATTRIBUTE_DEALLOC ((void (*) (void *)) free, 1)
+# else
+#  define _GL_ATTRIBUTE_DEALLOC_FREE \
+     _GL_ATTRIBUTE_DEALLOC (free, 1)
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_DEPRECATED: Declares that an entity is deprecated.
@@ -978,12 +1061,20 @@
      - enumeration, enumeration item,
      - typedef,
    in C++ also: namespace, class, template specialization.  */
-#if _GL_HAS_C_ATTRIBUTE (deprecated)
-# define _GL_ATTRIBUTE_DEPRECATED [[__deprecated__]]
-#elif _GL_HAS_ATTRIBUTE (deprecated)
-# define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
-#else
-# define _GL_ATTRIBUTE_DEPRECATED
+#ifndef _GL_ATTRIBUTE_DEPRECATED
+# ifndef _GL_BRACKET_BEFORE_ATTRIBUTE
+#  if _GL_HAVE___HAS_C_ATTRIBUTE
+#   if __has_c_attribute (__deprecated__)
+#    define _GL_ATTRIBUTE_DEPRECATED [[__deprecated__]]
+#   endif
+#  endif
+# endif
+# if !defined _GL_ATTRIBUTE_DEPRECATED && _GL_HAS_ATTRIBUTE (deprecated)
+#  define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
+# endif
+# ifndef _GL_ATTRIBUTE_DEPRECATED
+#  define _GL_ATTRIBUTE_DEPRECATED
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_ERROR(msg) requests an error if a function is called and
@@ -991,24 +1082,28 @@
    _GL_ATTRIBUTE_WARNING(msg) requests a warning if a function is called and
    the function call is not optimized away.  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (error)
-# define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__error__ (msg)))
-# define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__warning__ (msg)))
-#elif _GL_HAS_ATTRIBUTE (diagnose_if)
-# define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__diagnose_if__ (1, msg, "error")))
-# define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__diagnose_if__ (1, msg, "warning")))
-#else
-# define _GL_ATTRIBUTE_ERROR(msg)
-# define _GL_ATTRIBUTE_WARNING(msg)
+#if !(defined _GL_ATTRIBUTE_ERROR && defined _GL_ATTRIBUTE_WARNING)
+# if _GL_HAS_ATTRIBUTE (error)
+#  define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__error__ (msg)))
+#  define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__warning__ (msg)))
+# elif _GL_HAS_ATTRIBUTE (diagnose_if)
+#  define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__diagnose_if__ (1, msg, "error")))
+#  define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__diagnose_if__ (1, msg, "warning")))
+# else
+#  define _GL_ATTRIBUTE_ERROR(msg)
+#  define _GL_ATTRIBUTE_WARNING(msg)
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_EXTERNALLY_VISIBLE declares that the entity should remain
    visible to debuggers etc., even with '-fwhole-program'.  */
 /* Applies to: functions, variables.  */
-#if _GL_HAS_ATTRIBUTE (externally_visible)
-# define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE __attribute__ ((externally_visible))
-#else
-# define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
+#ifndef _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
+# if _GL_HAS_ATTRIBUTE (externally_visible)
+#  define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE __attribute__ ((externally_visible))
+# else
+#  define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_FALLTHROUGH declares that it is not a programming mistake if
@@ -1016,12 +1111,18 @@
    'default' label.  The compiler should not warn in this case.  */
 /* Applies to: Empty statement (;), inside a 'switch' statement.  */
 /* Always expands to something.  */
-#if _GL_HAS_C_ATTRIBUTE (fallthrough)
-# define _GL_ATTRIBUTE_FALLTHROUGH [[__fallthrough__]]
-#elif _GL_HAS_ATTRIBUTE (fallthrough)
-# define _GL_ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__))
-#else
-# define _GL_ATTRIBUTE_FALLTHROUGH ((void) 0)
+#ifndef _GL_ATTRIBUTE_FALLTHROUGH
+# if _GL_HAVE___HAS_C_ATTRIBUTE
+#  if __has_c_attribute (__fallthrough__)
+#   define _GL_ATTRIBUTE_FALLTHROUGH [[__fallthrough__]]
+#  endif
+# endif
+# if !defined _GL_ATTRIBUTE_FALLTHROUGH && _GL_HAS_ATTRIBUTE (fallthrough)
+#  define _GL_ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__))
+# endif
+# ifndef _GL_ATTRIBUTE_FALLTHROUGH
+#  define _GL_ATTRIBUTE_FALLTHROUGH ((void) 0)
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_FORMAT ((ARCHETYPE, STRING-INDEX, FIRST-TO-CHECK))
@@ -1035,10 +1136,12 @@
    If FIRST-TO-CHECK is not 0, arguments starting at FIRST-TO_CHECK
    are suitable for the format string.  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (format)
-# define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
-#else
-# define _GL_ATTRIBUTE_FORMAT(spec)
+#ifndef _GL_ATTRIBUTE_FORMAT
+# if _GL_HAS_ATTRIBUTE (format)
+#  define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+# else
+#  define _GL_ATTRIBUTE_FORMAT(spec)
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_LEAF declares that if the function is called from some other
@@ -1046,19 +1149,23 @@
    exception handling.  This declaration lets the compiler optimize that unit
    more aggressively.  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (leaf)
-# define _GL_ATTRIBUTE_LEAF __attribute__ ((__leaf__))
-#else
-# define _GL_ATTRIBUTE_LEAF
+#ifndef _GL_ATTRIBUTE_LEAF
+# if _GL_HAS_ATTRIBUTE (leaf)
+#  define _GL_ATTRIBUTE_LEAF __attribute__ ((__leaf__))
+# else
+#  define _GL_ATTRIBUTE_LEAF
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_MALLOC declares that the function returns a pointer to freshly
    allocated memory.  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (malloc)
-# define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
-#else
-# define _GL_ATTRIBUTE_MALLOC
+#ifndef _GL_ATTRIBUTE_MALLOC
+# if _GL_HAS_ATTRIBUTE (malloc)
+#  define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
+# else
+#  define _GL_ATTRIBUTE_MALLOC
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_MAY_ALIAS declares that pointers to the type may point to the
@@ -1066,10 +1173,12 @@
    strict aliasing optimization.  */
 /* Applies to: types.  */
 /* Oracle Studio 12.6 mishandles may_alias despite __has_attribute OK.  */
-#if _GL_HAS_ATTRIBUTE (may_alias) && !defined __SUNPRO_C
-# define _GL_ATTRIBUTE_MAY_ALIAS __attribute__ ((__may_alias__))
-#else
-# define _GL_ATTRIBUTE_MAY_ALIAS
+#ifndef _GL_ATTRIBUTE_MAY_ALIAS
+# if _GL_HAS_ATTRIBUTE (may_alias) && !defined __SUNPRO_C
+#  define _GL_ATTRIBUTE_MAY_ALIAS __attribute__ ((__may_alias__))
+# else
+#  define _GL_ATTRIBUTE_MAY_ALIAS
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_MAYBE_UNUSED declares that it is not a programming mistake if
@@ -1081,15 +1190,29 @@
      - enumeration, enumeration item,
      - typedef,
    in C++ also: class.  */
-/* In C++ and C2x, this is spelled [[__maybe_unused__]].
+/* In C++ and C23, this is spelled [[__maybe_unused__]].
    GCC's syntax is __attribute__ ((__unused__)).
-   clang supports both syntaxes.  */
-#if _GL_HAS_C_ATTRIBUTE (maybe_unused)
-# define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]]
-#else
-# define _GL_ATTRIBUTE_MAYBE_UNUSED _GL_ATTRIBUTE_UNUSED
+   clang supports both syntaxes.  Except that with clang ≥ 6, < 10, in C++ mode,
+   __has_c_attribute (__maybe_unused__) yields true but the use of
+   [[__maybe_unused__]] nevertheless produces a warning.  */
+#ifndef _GL_ATTRIBUTE_MAYBE_UNUSED
+# ifndef _GL_BRACKET_BEFORE_ATTRIBUTE
+#  if defined __clang__ && defined __cplusplus
+#   if !defined __apple_build_version__ && __clang_major__ >= 10
+#    define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]]
+#   endif
+#  elif _GL_HAVE___HAS_C_ATTRIBUTE
+#   if __has_c_attribute (__maybe_unused__)
+#    define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]]
+#   endif
+#  endif
+# endif
+# ifndef _GL_ATTRIBUTE_MAYBE_UNUSED
+#  define _GL_ATTRIBUTE_MAYBE_UNUSED _GL_ATTRIBUTE_UNUSED
+# endif
 #endif
-/* Alternative spelling of this macro, for convenience.  */
+/* Alternative spelling of this macro, for convenience and for
+   compatibility with glibc/include/libc-symbols.h.  */
 #define _GL_UNUSED _GL_ATTRIBUTE_MAYBE_UNUSED
 /* Earlier spellings of this macro.  */
 #define _UNUSED_PARAMETER_ _GL_ATTRIBUTE_MAYBE_UNUSED
@@ -1098,21 +1221,40 @@
    discard the return value.  The compiler may warn if the caller does not use
    the return value, unless the caller uses something like ignore_value.  */
 /* Applies to: function, enumeration, class.  */
-#if _GL_HAS_C_ATTRIBUTE (nodiscard)
-# define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]]
-#elif _GL_HAS_ATTRIBUTE (warn_unused_result)
-# define _GL_ATTRIBUTE_NODISCARD __attribute__ ((__warn_unused_result__))
-#else
-# define _GL_ATTRIBUTE_NODISCARD
+#ifndef _GL_ATTRIBUTE_NODISCARD
+# ifndef _GL_BRACKET_BEFORE_ATTRIBUTE
+#  if defined __clang__ && defined __cplusplus
+  /* With clang up to 15.0.6 (at least), in C++ mode, [[__nodiscard__]] produces
+     a warning.
+     The 1000 below means a yet unknown threshold.  When clang++ version X
+     starts supporting [[__nodiscard__]] without warning about it, you can
+     replace the 1000 with X.  */
+#   if __clang_major__ >= 1000
+#    define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]]
+#   endif
+#  elif _GL_HAVE___HAS_C_ATTRIBUTE
+#   if __has_c_attribute (__nodiscard__)
+#    define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]]
+#   endif
+#  endif
+# endif
+# if !defined _GL_ATTRIBUTE_NODISCARD && _GL_HAS_ATTRIBUTE (warn_unused_result)
+#  define _GL_ATTRIBUTE_NODISCARD __attribute__ ((__warn_unused_result__))
+# endif
+# ifndef _GL_ATTRIBUTE_NODISCARD
+#  define _GL_ATTRIBUTE_NODISCARD
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_NOINLINE tells that the compiler should not inline the
    function.  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (noinline)
-# define _GL_ATTRIBUTE_NOINLINE __attribute__ ((__noinline__))
-#else
-# define _GL_ATTRIBUTE_NOINLINE
+#ifndef _GL_ATTRIBUTE_NOINLINE
+# if _GL_HAS_ATTRIBUTE (noinline)
+#  define _GL_ATTRIBUTE_NOINLINE __attribute__ ((__noinline__))
+# else
+#  define _GL_ATTRIBUTE_NOINLINE
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_NONNULL ((N1, N2,...)) declares that the arguments N1, N2,...
@@ -1120,20 +1262,24 @@
    _GL_ATTRIBUTE_NONNULL () declares that all pointer arguments must not be
    null.  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (nonnull)
-# define _GL_ATTRIBUTE_NONNULL(args) __attribute__ ((__nonnull__ args))
-#else
-# define _GL_ATTRIBUTE_NONNULL(args)
+#ifndef _GL_ATTRIBUTE_NONNULL
+# if _GL_HAS_ATTRIBUTE (nonnull)
+#  define _GL_ATTRIBUTE_NONNULL(args) __attribute__ ((__nonnull__ args))
+# else
+#  define _GL_ATTRIBUTE_NONNULL(args)
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_NONSTRING declares that the contents of a character array is
    not meant to be NUL-terminated.  */
 /* Applies to: struct/union members and variables that are arrays of element
    type '[[un]signed] char'.  */
-#if _GL_HAS_ATTRIBUTE (nonstring)
-# define _GL_ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__))
-#else
-# define _GL_ATTRIBUTE_NONSTRING
+#ifndef _GL_ATTRIBUTE_NONSTRING
+# if _GL_HAS_ATTRIBUTE (nonstring)
+#  define _GL_ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__))
+# else
+#  define _GL_ATTRIBUTE_NONSTRING
+# endif
 #endif
 
 /* There is no _GL_ATTRIBUTE_NORETURN; use _Noreturn instead.  */
@@ -1141,10 +1287,26 @@
 /* _GL_ATTRIBUTE_NOTHROW declares that the function does not throw exceptions.
  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (nothrow) && !defined __cplusplus
-# define _GL_ATTRIBUTE_NOTHROW __attribute__ ((__nothrow__))
-#else
-# define _GL_ATTRIBUTE_NOTHROW
+/* After a function's parameter list, this attribute must come first, before
+   other attributes.  */
+#ifndef _GL_ATTRIBUTE_NOTHROW
+# if defined __cplusplus
+#  if _GL_GNUC_PREREQ (2, 8) || __clang_major >= 4
+#   if __cplusplus >= 201103L
+#    define _GL_ATTRIBUTE_NOTHROW noexcept (true)
+#   else
+#    define _GL_ATTRIBUTE_NOTHROW throw ()
+#   endif
+#  else
+#   define _GL_ATTRIBUTE_NOTHROW
+#  endif
+# else
+#  if _GL_HAS_ATTRIBUTE (nothrow)
+#   define _GL_ATTRIBUTE_NOTHROW __attribute__ ((__nothrow__))
+#  else
+#   define _GL_ATTRIBUTE_NOTHROW
+#  endif
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_PACKED declares:
@@ -1153,10 +1315,12 @@
    minimizing the memory required.  */
 /* Applies to: struct members, struct, union,
    in C++ also: class.  */
-#if _GL_HAS_ATTRIBUTE (packed)
-# define _GL_ATTRIBUTE_PACKED __attribute__ ((__packed__))
-#else
-# define _GL_ATTRIBUTE_PACKED
+#ifndef _GL_ATTRIBUTE_PACKED
+# if _GL_HAS_ATTRIBUTE (packed)
+#  define _GL_ATTRIBUTE_PACKED __attribute__ ((__packed__))
+# else
+#  define _GL_ATTRIBUTE_PACKED
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_PURE declares that It is OK for a compiler to omit duplicate
@@ -1166,19 +1330,23 @@
    observable state, and always returns exactly once.
    (This attribute is looser than _GL_ATTRIBUTE_CONST.)  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (pure)
-# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
-#else
-# define _GL_ATTRIBUTE_PURE
+#ifndef _GL_ATTRIBUTE_PURE
+# if _GL_HAS_ATTRIBUTE (pure)
+#  define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
+# else
+#  define _GL_ATTRIBUTE_PURE
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_RETURNS_NONNULL declares that the function's return value is
    a non-NULL pointer.  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (returns_nonnull)
-# define _GL_ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__))
-#else
-# define _GL_ATTRIBUTE_RETURNS_NONNULL
+#ifndef _GL_ATTRIBUTE_RETURNS_NONNULL
+# if _GL_HAS_ATTRIBUTE (returns_nonnull)
+#  define _GL_ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__))
+# else
+#  define _GL_ATTRIBUTE_RETURNS_NONNULL
+# endif
 #endif
 
 /* _GL_ATTRIBUTE_SENTINEL(pos) declares that the variadic function expects a
@@ -1186,17 +1354,21 @@
    _GL_ATTRIBUTE_SENTINEL () - The last argument is NULL (requires C99).
    _GL_ATTRIBUTE_SENTINEL ((N)) - The (N+1)st argument from the end is NULL.  */
 /* Applies to: functions.  */
-#if _GL_HAS_ATTRIBUTE (sentinel)
-# define _GL_ATTRIBUTE_SENTINEL(pos) __attribute__ ((__sentinel__ pos))
-#else
-# define _GL_ATTRIBUTE_SENTINEL(pos)
+#ifndef _GL_ATTRIBUTE_SENTINEL
+# if _GL_HAS_ATTRIBUTE (sentinel)
+#  define _GL_ATTRIBUTE_SENTINEL(pos) __attribute__ ((__sentinel__ pos))
+# else
+#  define _GL_ATTRIBUTE_SENTINEL(pos)
+# endif
 #endif
 
 /* A helper macro.  Don't use it directly.  */
-#if _GL_HAS_ATTRIBUTE (unused)
-# define _GL_ATTRIBUTE_UNUSED __attribute__ ((__unused__))
-#else
-# define _GL_ATTRIBUTE_UNUSED
+#ifndef _GL_ATTRIBUTE_UNUSED
+# if _GL_HAS_ATTRIBUTE (unused)
+#  define _GL_ATTRIBUTE_UNUSED __attribute__ ((__unused__))
+# else
+#  define _GL_ATTRIBUTE_UNUSED
+# endif
 #endif
 
 
@@ -1206,10 +1378,24 @@
 /* Applies to: label (both in C and C++).  */
 /* Note that g++ < 4.5 does not support the '__attribute__ ((__unused__)) ;'
    syntax.  But clang does.  */
-#if !(defined __cplusplus && !_GL_GNUC_PREREQ (4, 5)) || defined __clang__
-# define _GL_UNUSED_LABEL _GL_ATTRIBUTE_UNUSED
+#ifndef _GL_UNUSED_LABEL
+# if !(defined __cplusplus && !_GL_GNUC_PREREQ (4, 5)) || defined __clang__
+#  define _GL_UNUSED_LABEL _GL_ATTRIBUTE_UNUSED
+# else
+#  define _GL_UNUSED_LABEL
+# endif
+#endif
+
+
+/* In C++, there is the concept of "language linkage", that encompasses
+    name mangling and function calling conventions.
+    The following macros start and end a block of "C" linkage.  */
+#ifdef __cplusplus
+# define _GL_BEGIN_C_LINKAGE extern "C" {
+# define _GL_END_C_LINKAGE }
 #else
-# define _GL_UNUSED_LABEL
+# define _GL_BEGIN_C_LINKAGE
+# define _GL_END_C_LINKAGE
 #endif
 
 
@@ -1292,3 +1478,37 @@
 
 /* Define as a macro for copying va_list variables. */
 /* #undef va_copy */
+
+#ifndef HAVE_C_BOOL
+# if !defined __cplusplus && !defined __bool_true_false_are_defined
+#  if HAVE_STDBOOL_H
+#   include <stdbool.h>
+#  else
+#   if defined __SUNPRO_C
+#    error "<stdbool.h> is not usable with this configuration. To make it usable, add -D_STDC_C99= to $CC."
+#   else
+#    error "<stdbool.h> does not exist on this platform. Use gnulib module 'stdbool-c99' instead of gnulib module 'stdbool'."
+#   endif
+#  endif
+# endif
+# if !true
+#  define true (!false)
+# endif
+#endif
+
+#if (!defined HAVE_C_STATIC_ASSERT && !defined assert \
+     && (!defined __cplusplus \
+         || (__cpp_static_assert < 201411 \
+             && __GNUG__ < 6 && __clang_major__ < 6)))
+ #include <assert.h>
+ #undef/**/assert
+ #ifdef __sgi
+  #undef/**/__ASSERT_H__
+ #endif
+ /* Solaris 11.4 <assert.h> defines static_assert as a macro with 2 arguments.
+    We need it also to be invocable with a single argument.  */
+ #if defined __sun && (__STDC_VERSION__ - 0 >= 201112L) && !defined __cplusplus
+  #undef/**/static_assert
+  #define static_assert _Static_assert
+ #endif
+#endif