Update from Gnulib

This incorporates:
2020-09-05 verify: avoid __builtin_assume
2020-08-30 strerrorname_np: New module
2020-08-26 include_next, stdint, time_rz: Change configure message
* lib/gnulib.mk.in: Regenerate.
* lib/string.in.h, lib/verify.h, m4/include_next.m4, m4/stdint.m4:
* m4/string_h.m4, m4/time_rz.m4: Copy from Gnulib.

lib/gnulib.mk.in

@@ -442,6 +442,7 @@ GNULIB_STRCASESTR = @GNULIB_STRCASESTR@
 GNULIB_STRCHRNUL = @GNULIB_STRCHRNUL@
 GNULIB_STRDUP = @GNULIB_STRDUP@
 GNULIB_STRERROR = @GNULIB_STRERROR@
+GNULIB_STRERRORNAME_NP = @GNULIB_STRERRORNAME_NP@
 GNULIB_STRERROR_R = @GNULIB_STRERROR_R@
 GNULIB_STRFTIME = @GNULIB_STRFTIME@
 GNULIB_STRNCAT = @GNULIB_STRNCAT@
@@ -662,6 +663,7 @@ HAVE_STPCPY = @HAVE_STPCPY@
 HAVE_STPNCPY = @HAVE_STPNCPY@
 HAVE_STRCASESTR = @HAVE_STRCASESTR@
 HAVE_STRCHRNUL = @HAVE_STRCHRNUL@
+HAVE_STRERRORNAME_NP = @HAVE_STRERRORNAME_NP@
 HAVE_STRPBRK = @HAVE_STRPBRK@
 HAVE_STRPTIME = @HAVE_STRPTIME@
 HAVE_STRSEP = @HAVE_STRSEP@
@@ -965,6 +967,7 @@ REPLACE_STRCASESTR = @REPLACE_STRCASESTR@
 REPLACE_STRCHRNUL = @REPLACE_STRCHRNUL@
 REPLACE_STRDUP = @REPLACE_STRDUP@
 REPLACE_STRERROR = @REPLACE_STRERROR@
+REPLACE_STRERRORNAME_NP = @REPLACE_STRERRORNAME_NP@
 REPLACE_STRERROR_R = @REPLACE_STRERROR_R@
 REPLACE_STRFTIME = @REPLACE_STRFTIME@
 REPLACE_STRNCAT = @REPLACE_STRNCAT@
@@ -2859,6 +2862,7 @@ string.h: string.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
 	      -e 's/@''GNULIB_STRTOK_R''@/$(GNULIB_STRTOK_R)/g' \
 	      -e 's/@''GNULIB_STRERROR''@/$(GNULIB_STRERROR)/g' \
 	      -e 's/@''GNULIB_STRERROR_R''@/$(GNULIB_STRERROR_R)/g' \
+	      -e 's/@''GNULIB_STRERRORNAME_NP''@/$(GNULIB_STRERRORNAME_NP)/g' \
 	      -e 's/@''GNULIB_SIGABBREV_NP''@/$(GNULIB_SIGABBREV_NP)/g' \
 	      -e 's/@''GNULIB_SIGDESCR_NP''@/$(GNULIB_SIGDESCR_NP)/g' \
 	      -e 's/@''GNULIB_STRSIGNAL''@/$(GNULIB_STRSIGNAL)/g' \
@@ -2883,6 +2887,7 @@ string.h: string.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
 	      -e 's|@''HAVE_STRCASESTR''@|$(HAVE_STRCASESTR)|g' \
 	      -e 's|@''HAVE_DECL_STRTOK_R''@|$(HAVE_DECL_STRTOK_R)|g' \
 	      -e 's|@''HAVE_DECL_STRERROR_R''@|$(HAVE_DECL_STRERROR_R)|g' \
+	      -e 's|@''HAVE_STRERRORNAME_NP''@|$(HAVE_STRERRORNAME_NP)|g' \
 	      -e 's|@''HAVE_SIGABBREV_NP''@|$(HAVE_SIGABBREV_NP)|g' \
 	      -e 's|@''HAVE_SIGDESCR_NP''@|$(HAVE_SIGDESCR_NP)|g' \
 	      -e 's|@''HAVE_DECL_STRSIGNAL''@|$(HAVE_DECL_STRSIGNAL)|g' \
@@ -2900,6 +2905,7 @@ string.h: string.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
 	      -e 's|@''REPLACE_STRTOK_R''@|$(REPLACE_STRTOK_R)|g' \
 	      -e 's|@''REPLACE_STRERROR''@|$(REPLACE_STRERROR)|g' \
 	      -e 's|@''REPLACE_STRERROR_R''@|$(REPLACE_STRERROR_R)|g' \
+	      -e 's|@''REPLACE_STRERRORNAME_NP''@|$(REPLACE_STRERRORNAME_NP)|g' \
 	      -e 's|@''REPLACE_STRSIGNAL''@|$(REPLACE_STRSIGNAL)|g' \
 	      -e 's|@''UNDEFINE_STRTOK_R''@|$(UNDEFINE_STRTOK_R)|g' \
 	      -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \

lib/string.in.h

@@ -1045,6 +1045,30 @@ _GL_WARN_ON_USE (strerror_r, "strerror_r is unportable - "
 # endif
 #endif
 
+/* Return the name of the system error code ERRNUM.  */
+#if @GNULIB_STRERRORNAME_NP@
+# if @REPLACE_STRERRORNAME_NP@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef strerrorname_np
+#   define strerrorname_np rpl_strerrorname_np
+#  endif
+_GL_FUNCDECL_RPL (strerrorname_np, const char *, (int errnum));
+_GL_CXXALIAS_RPL (strerrorname_np, const char *, (int errnum));
+# else
+#  if !@HAVE_STRERRORNAME_NP@
+_GL_FUNCDECL_SYS (strerrorname_np, const char *, (int errnum));
+#  endif
+_GL_CXXALIAS_SYS (strerrorname_np, const char *, (int errnum));
+# endif
+_GL_CXXALIASWARN (strerrorname_np);
+#elif defined GNULIB_POSIXCHECK
+# undef strerrorname_np
+# if HAVE_RAW_DECL_STRERRORNAME_NP
+_GL_WARN_ON_USE (strerrorname_np, "strerrorname_np is unportable - "
+                 "use gnulib module strerrorname_np for portability");
+# endif
+#endif
+
 /* Return an abbreviation string for the signal number SIG.  */
 #if @GNULIB_SIGABBREV_NP@
 # if ! @HAVE_SIGABBREV_NP@

lib/verify.h

@@ -246,13 +246,6 @@ template <int w>
 
 /* @assert.h omit start@  */
 
-#if defined __has_builtin
-/* <https://clang.llvm.org/docs/LanguageExtensions.html#builtin-functions> */
-# define _GL_HAS_BUILTIN_ASSUME __has_builtin (__builtin_assume)
-#else
-# define _GL_HAS_BUILTIN_ASSUME 0
-#endif
-
 #if 3 < __GNUC__ + (3 < __GNUC_MINOR__ + (4 <= __GNUC_PATCHLEVEL__))
 # define _GL_HAS_BUILTIN_TRAP 1
 #elif defined __has_builtin
@@ -312,36 +305,14 @@ template <int w>
 
    Although assuming R can help a compiler generate better code or
    diagnostics, performance can suffer if R uses hard-to-optimize
-   features such as function calls not inlined by the compiler.  */
+   features such as function calls not inlined by the compiler.
 
-/* Use __builtin_assume in preference to __builtin_unreachable, because
+   Avoid Clang's __builtin_assume, as it breaks GNU Emacs master
-   in clang versions 8.0.x and older, the definition based on
+   as of 2020-08-23T21:09:49Z!eggert@cs.ucla.edu; see
-   __builtin_assume has an effect on optimizations, whereas the definition
+   <https://bugs.gnu.org/43152#71>.  It's not known whether this breakage
-   based on __builtin_unreachable does not.  (GCC so far has only
+   is a Clang bug or an Emacs bug; play it safe for now.  */
-   __builtin_unreachable.)  */
+
-#if _GL_HAS_BUILTIN_ASSUME
+#if _GL_HAS_BUILTIN_UNREACHABLE
-/* Use __builtin_constant_p to help clang's data-flow analysis for the case
-   assume (0).
-   Use a temporary variable, to avoid a clang warning
-   "the argument to '__builtin_assume' has side effects that will be discarded"
-   if R contains invocations of functions not marked as 'const'.
-   The type of the temporary variable can't be __typeof__ (R), because that
-   does not work on bit field expressions.  Use '_Bool' or 'bool' as type
-   instead.  */
-# if defined __cplusplus
-#  define assume(R) \
-     (__builtin_constant_p (R) && !(R) \
-      ? (void) __builtin_unreachable () \
-      : (void) ({ bool _gl_verify_temp = (R); \
-                  __builtin_assume (_gl_verify_temp); }))
-# else
-#  define assume(R) \
-     (__builtin_constant_p (R) && !(R) \
-      ? (void) __builtin_unreachable () \
-      : (void) ({ _Bool _gl_verify_temp = (R); \
-                  __builtin_assume (_gl_verify_temp); }))
-# endif
-#elif _GL_HAS_BUILTIN_UNREACHABLE
 # define assume(R) ((R) ? (void) 0 : __builtin_unreachable ())
 #elif 1200 <= _MSC_VER
 # define assume(R) __assume (R)

m4/include_next.m4

@@ -1,4 +1,4 @@
-# include_next.m4 serial 25
+# include_next.m4 serial 26
 dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -106,19 +106,21 @@ dnl We intentionally avoid using AC_LANG_SOURCE here.
   AC_SUBST([INCLUDE_NEXT])
   AC_SUBST([INCLUDE_NEXT_AS_FIRST_DIRECTIVE])
   AC_SUBST([PRAGMA_SYSTEM_HEADER])
-  AC_CACHE_CHECK([whether system header files limit the line length],
+
-    [gl_cv_pragma_columns],
+  dnl HP NonStop systems, which define __TANDEM, limit the line length
-    [dnl HP NonStop systems, which define __TANDEM, have this misfeature.
+  dnl after including some system header files.
-     AC_EGREP_CPP([choke me],
+  AC_CACHE_CHECK([whether source code line length is unlimited],
+    [gl_cv_source_line_length_unlimited],
+    [AC_EGREP_CPP([choke me],
        [
 #ifdef __TANDEM
 choke me
 #endif
        ],
-       [gl_cv_pragma_columns=yes],
+       [gl_cv_source_line_length_unlimited=no],
-       [gl_cv_pragma_columns=no])
+       [gl_cv_source_line_length_unlimited=yes])
     ])
-  if test $gl_cv_pragma_columns = yes; then
+  if test $gl_cv_source_line_length_unlimited = no; then
     PRAGMA_COLUMNS="#pragma COLUMNS 10000"
   else
     PRAGMA_COLUMNS=

m4/stdint.m4

@@ -1,4 +1,4 @@
-# stdint.m4 serial 55
+# stdint.m4 serial 56
 dnl Copyright (C) 2001-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -302,9 +302,10 @@ static const char *macro_values[] =
       HAVE_C99_STDINT_H=1
       dnl Now see whether the system <stdint.h> works without
       dnl __STDC_CONSTANT_MACROS/__STDC_LIMIT_MACROS defined.
-      AC_CACHE_CHECK([whether stdint.h predates C++11],
+      dnl If not, there would be problems when stdint.h is included from C++.
-        [gl_cv_header_stdint_predates_cxx11_h],
+      AC_CACHE_CHECK([whether stdint.h works without ISO C predefines],
-        [gl_cv_header_stdint_predates_cxx11_h=yes
+        [gl_cv_header_stdint_without_STDC_macros],
+        [gl_cv_header_stdint_without_STDC_macros=no
          AC_COMPILE_IFELSE([
            AC_LANG_PROGRAM([[
 #define _GL_JUST_INCLUDE_SYSTEM_STDINT_H 1 /* work if build isn't clean */
@@ -315,13 +316,14 @@ gl_STDINT_INCLUDES
 intmax_t im = INTMAX_MAX;
 int32_t i32 = INT32_C (0x7fffffff);
            ]])],
-           [gl_cv_header_stdint_predates_cxx11_h=no])])
+           [gl_cv_header_stdint_without_STDC_macros=yes])
+        ])
 
-      if test "$gl_cv_header_stdint_predates_cxx11_h" = yes; then
+      if test $gl_cv_header_stdint_without_STDC_macros = no; then
         AC_DEFINE([__STDC_CONSTANT_MACROS], [1],
-                  [Define to 1 if the system <stdint.h> predates C++11.])
+          [Define to 1 if the system <stdint.h> predates C++11.])
         AC_DEFINE([__STDC_LIMIT_MACROS], [1],
-                  [Define to 1 if the system <stdint.h> predates C++11.])
+          [Define to 1 if the system <stdint.h> predates C++11.])
       fi
       AC_CACHE_CHECK([whether stdint.h has UINTMAX_WIDTH etc.],
         [gl_cv_header_stdint_width],

m4/string_h.m4

@@ -5,7 +5,7 @@
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
-# serial 26
+# serial 27
 
 # Written by Paul Eggert.
 
@@ -28,7 +28,7 @@ AC_DEFUN([gl_HEADER_STRING_H_BODY],
     ]],
     [ffsl ffsll memmem mempcpy memrchr rawmemchr stpcpy stpncpy strchrnul
      strdup strncat strndup strnlen strpbrk strsep strcasestr strtok_r
-     strerror_r sigabbrev_np sigdescr_np strsignal strverscmp])
+     strerror_r strerrorname_np sigabbrev_np sigdescr_np strsignal strverscmp])
 
   AC_REQUIRE([AC_C_RESTRICT])
 ])
@@ -44,47 +44,48 @@ AC_DEFUN([gl_STRING_MODULE_INDICATOR],
 
 AC_DEFUN([gl_HEADER_STRING_H_DEFAULTS],
 [
-  GNULIB_EXPLICIT_BZERO=0; AC_SUBST([GNULIB_EXPLICIT_BZERO])
+  GNULIB_EXPLICIT_BZERO=0;   AC_SUBST([GNULIB_EXPLICIT_BZERO])
-  GNULIB_FFSL=0;        AC_SUBST([GNULIB_FFSL])
+  GNULIB_FFSL=0;             AC_SUBST([GNULIB_FFSL])
-  GNULIB_FFSLL=0;       AC_SUBST([GNULIB_FFSLL])
+  GNULIB_FFSLL=0;            AC_SUBST([GNULIB_FFSLL])
-  GNULIB_MEMCHR=0;      AC_SUBST([GNULIB_MEMCHR])
+  GNULIB_MEMCHR=0;           AC_SUBST([GNULIB_MEMCHR])
-  GNULIB_MEMMEM=0;      AC_SUBST([GNULIB_MEMMEM])
+  GNULIB_MEMMEM=0;           AC_SUBST([GNULIB_MEMMEM])
-  GNULIB_MEMPCPY=0;     AC_SUBST([GNULIB_MEMPCPY])
+  GNULIB_MEMPCPY=0;          AC_SUBST([GNULIB_MEMPCPY])
-  GNULIB_MEMRCHR=0;     AC_SUBST([GNULIB_MEMRCHR])
+  GNULIB_MEMRCHR=0;          AC_SUBST([GNULIB_MEMRCHR])
-  GNULIB_RAWMEMCHR=0;   AC_SUBST([GNULIB_RAWMEMCHR])
+  GNULIB_RAWMEMCHR=0;        AC_SUBST([GNULIB_RAWMEMCHR])
-  GNULIB_STPCPY=0;      AC_SUBST([GNULIB_STPCPY])
+  GNULIB_STPCPY=0;           AC_SUBST([GNULIB_STPCPY])
-  GNULIB_STPNCPY=0;     AC_SUBST([GNULIB_STPNCPY])
+  GNULIB_STPNCPY=0;          AC_SUBST([GNULIB_STPNCPY])
-  GNULIB_STRCHRNUL=0;   AC_SUBST([GNULIB_STRCHRNUL])
+  GNULIB_STRCHRNUL=0;        AC_SUBST([GNULIB_STRCHRNUL])
-  GNULIB_STRDUP=0;      AC_SUBST([GNULIB_STRDUP])
+  GNULIB_STRDUP=0;           AC_SUBST([GNULIB_STRDUP])
-  GNULIB_STRNCAT=0;     AC_SUBST([GNULIB_STRNCAT])
+  GNULIB_STRNCAT=0;          AC_SUBST([GNULIB_STRNCAT])
-  GNULIB_STRNDUP=0;     AC_SUBST([GNULIB_STRNDUP])
+  GNULIB_STRNDUP=0;          AC_SUBST([GNULIB_STRNDUP])
-  GNULIB_STRNLEN=0;     AC_SUBST([GNULIB_STRNLEN])
+  GNULIB_STRNLEN=0;          AC_SUBST([GNULIB_STRNLEN])
-  GNULIB_STRPBRK=0;     AC_SUBST([GNULIB_STRPBRK])
+  GNULIB_STRPBRK=0;          AC_SUBST([GNULIB_STRPBRK])
-  GNULIB_STRSEP=0;      AC_SUBST([GNULIB_STRSEP])
+  GNULIB_STRSEP=0;           AC_SUBST([GNULIB_STRSEP])
-  GNULIB_STRSTR=0;      AC_SUBST([GNULIB_STRSTR])
+  GNULIB_STRSTR=0;           AC_SUBST([GNULIB_STRSTR])
-  GNULIB_STRCASESTR=0;  AC_SUBST([GNULIB_STRCASESTR])
+  GNULIB_STRCASESTR=0;       AC_SUBST([GNULIB_STRCASESTR])
-  GNULIB_STRTOK_R=0;    AC_SUBST([GNULIB_STRTOK_R])
+  GNULIB_STRTOK_R=0;         AC_SUBST([GNULIB_STRTOK_R])
-  GNULIB_MBSLEN=0;      AC_SUBST([GNULIB_MBSLEN])
+  GNULIB_MBSLEN=0;           AC_SUBST([GNULIB_MBSLEN])
-  GNULIB_MBSNLEN=0;     AC_SUBST([GNULIB_MBSNLEN])
+  GNULIB_MBSNLEN=0;          AC_SUBST([GNULIB_MBSNLEN])
-  GNULIB_MBSCHR=0;      AC_SUBST([GNULIB_MBSCHR])
+  GNULIB_MBSCHR=0;           AC_SUBST([GNULIB_MBSCHR])
-  GNULIB_MBSRCHR=0;     AC_SUBST([GNULIB_MBSRCHR])
+  GNULIB_MBSRCHR=0;          AC_SUBST([GNULIB_MBSRCHR])
-  GNULIB_MBSSTR=0;      AC_SUBST([GNULIB_MBSSTR])
+  GNULIB_MBSSTR=0;           AC_SUBST([GNULIB_MBSSTR])
-  GNULIB_MBSCASECMP=0;  AC_SUBST([GNULIB_MBSCASECMP])
+  GNULIB_MBSCASECMP=0;       AC_SUBST([GNULIB_MBSCASECMP])
-  GNULIB_MBSNCASECMP=0; AC_SUBST([GNULIB_MBSNCASECMP])
+  GNULIB_MBSNCASECMP=0;      AC_SUBST([GNULIB_MBSNCASECMP])
-  GNULIB_MBSPCASECMP=0; AC_SUBST([GNULIB_MBSPCASECMP])
+  GNULIB_MBSPCASECMP=0;      AC_SUBST([GNULIB_MBSPCASECMP])
-  GNULIB_MBSCASESTR=0;  AC_SUBST([GNULIB_MBSCASESTR])
+  GNULIB_MBSCASESTR=0;       AC_SUBST([GNULIB_MBSCASESTR])
-  GNULIB_MBSCSPN=0;     AC_SUBST([GNULIB_MBSCSPN])
+  GNULIB_MBSCSPN=0;          AC_SUBST([GNULIB_MBSCSPN])
-  GNULIB_MBSPBRK=0;     AC_SUBST([GNULIB_MBSPBRK])
+  GNULIB_MBSPBRK=0;          AC_SUBST([GNULIB_MBSPBRK])
-  GNULIB_MBSSPN=0;      AC_SUBST([GNULIB_MBSSPN])
+  GNULIB_MBSSPN=0;           AC_SUBST([GNULIB_MBSSPN])
-  GNULIB_MBSSEP=0;      AC_SUBST([GNULIB_MBSSEP])
+  GNULIB_MBSSEP=0;           AC_SUBST([GNULIB_MBSSEP])
-  GNULIB_MBSTOK_R=0;    AC_SUBST([GNULIB_MBSTOK_R])
+  GNULIB_MBSTOK_R=0;         AC_SUBST([GNULIB_MBSTOK_R])
-  GNULIB_STRERROR=0;    AC_SUBST([GNULIB_STRERROR])
+  GNULIB_STRERROR=0;         AC_SUBST([GNULIB_STRERROR])
-  GNULIB_STRERROR_R=0;  AC_SUBST([GNULIB_STRERROR_R])
+  GNULIB_STRERROR_R=0;       AC_SUBST([GNULIB_STRERROR_R])
-  GNULIB_SIGABBREV_NP=0;AC_SUBST([GNULIB_SIGABBREV_NP])
+  GNULIB_STRERRORNAME_NP=0;  AC_SUBST([GNULIB_STRERRORNAME_NP])
-  GNULIB_SIGDESCR_NP=0; AC_SUBST([GNULIB_SIGDESCR_NP])
+  GNULIB_SIGABBREV_NP=0;     AC_SUBST([GNULIB_SIGABBREV_NP])
-  GNULIB_STRSIGNAL=0;   AC_SUBST([GNULIB_STRSIGNAL])
+  GNULIB_SIGDESCR_NP=0;      AC_SUBST([GNULIB_SIGDESCR_NP])
-  GNULIB_STRVERSCMP=0;  AC_SUBST([GNULIB_STRVERSCMP])
+  GNULIB_STRSIGNAL=0;        AC_SUBST([GNULIB_STRSIGNAL])
-  HAVE_MBSLEN=0;        AC_SUBST([HAVE_MBSLEN])
+  GNULIB_STRVERSCMP=0;       AC_SUBST([GNULIB_STRVERSCMP])
+  HAVE_MBSLEN=0;             AC_SUBST([HAVE_MBSLEN])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_EXPLICIT_BZERO=1;        AC_SUBST([HAVE_EXPLICIT_BZERO])
   HAVE_FFSL=1;                  AC_SUBST([HAVE_FFSL])
@@ -104,6 +105,7 @@ AC_DEFUN([gl_HEADER_STRING_H_DEFAULTS],
   HAVE_STRCASESTR=1;            AC_SUBST([HAVE_STRCASESTR])
   HAVE_DECL_STRTOK_R=1;         AC_SUBST([HAVE_DECL_STRTOK_R])
   HAVE_DECL_STRERROR_R=1;       AC_SUBST([HAVE_DECL_STRERROR_R])
+  HAVE_STRERRORNAME_NP=1;       AC_SUBST([HAVE_STRERRORNAME_NP])
   HAVE_SIGABBREV_NP=1;          AC_SUBST([HAVE_SIGABBREV_NP])
   HAVE_SIGDESCR_NP=1;           AC_SUBST([HAVE_SIGDESCR_NP])
   HAVE_DECL_STRSIGNAL=1;        AC_SUBST([HAVE_DECL_STRSIGNAL])
@@ -121,6 +123,7 @@ AC_DEFUN([gl_HEADER_STRING_H_DEFAULTS],
   REPLACE_STRTOK_R=0;           AC_SUBST([REPLACE_STRTOK_R])
   REPLACE_STRERROR=0;           AC_SUBST([REPLACE_STRERROR])
   REPLACE_STRERROR_R=0;         AC_SUBST([REPLACE_STRERROR_R])
+  REPLACE_STRERRORNAME_NP=0;    AC_SUBST([REPLACE_STRERRORNAME_NP])
   REPLACE_STRSIGNAL=0;          AC_SUBST([REPLACE_STRSIGNAL])
   UNDEFINE_STRTOK_R=0;          AC_SUBST([UNDEFINE_STRTOK_R])
 ])

m4/time_rz.m4

@@ -13,12 +13,12 @@ AC_DEFUN([gl_TIME_RZ],
   AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
   AC_REQUIRE([AC_STRUCT_TIMEZONE])
 
-  # Mac OS X 10.6 loops forever with some time_t values.
+  # On Mac OS X 10.6, localtime loops forever with some time_t values.
   # See Bug#27706, Bug#27736, and
   # https://lists.gnu.org/r/bug-gnulib/2017-07/msg00142.html
-  AC_CACHE_CHECK([whether localtime loops forever near extrema],
+  AC_CACHE_CHECK([whether localtime works even near extrema],
-    [gl_cv_func_localtime_infloop_bug],
+    [gl_cv_func_localtime_works],
-    [gl_cv_func_localtime_infloop_bug=no
+    [gl_cv_func_localtime_works=yes
      AC_RUN_IFELSE(
        [AC_LANG_PROGRAM(
           [[#include <stdlib.h>
@@ -37,10 +37,10 @@ AC_DEFUN([gl_TIME_RZ],
             return tm && tm->tm_isdst;
           ]])],
        [(TZ=QQQ0 ./conftest$EXEEXT) >/dev/null 2>&1 ||
-           gl_cv_func_localtime_infloop_bug=yes],
+           gl_cv_func_localtime_works=no],
        [],
-       [gl_cv_func_localtime_infloop_bug="guessing no"])])
+       [gl_cv_func_localtime_works="guessing yes"])])
-  if test "$gl_cv_func_localtime_infloop_bug" = yes; then
+  if test "$gl_cv_func_localtime_works" = no; then
       AC_DEFINE([HAVE_LOCALTIME_INFLOOP_BUG], 1,
         [Define if localtime-like functions can loop forever on
          extreme arguments.])