Update from Gnulib by running admin/merge-gnulib

* admin/merge-gnulib (AVOIDED_MODULES): Add strncpy, as Emacs is not
likely to exercise the FreeBSD 15 strncpy bug that this module fixes.
* lib/issymlinkat.h: New file, taken from Gnulib.

16 files changed, 262 insertions, 135 deletions

diff --git a/lib/attribute.h b/lib/attribute.h
index c85412d90af..f24f5b18f1e 100644
--- a/lib/attribute.h
+++ b/lib/attribute.h
@@ -257,7 +257,7 @@
    calls to the function with the same arguments, so long as the state
    addressed by its arguments is the same.
    This attribute is safe for a function that is effectless, idempotent,
-   stateless, and independent; see ISO C 23 § 6.7.12.7 for a definition of
+   stateless, and independent; see ISO C 23 § 6.7.13.8 for a definition of
    these terms.
    (This attribute is stricter than REPRODUCIBLE because the function
    must be stateless and independent.  It is looser than ATTRIBUTE_CONST
@@ -266,7 +266,7 @@
    See also <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2956.htm> and
    <https://stackoverflow.com/questions/76847905/>.
    ATTENTION! Efforts are underway to change the meaning of this attribute.
-   See <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3424.htm>.  */
+   See <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3494.htm>.  */
 /* Applies to: functions, pointer to functions, function type.  */
 #define UNSEQUENCED _GL_ATTRIBUTE_UNSEQUENCED
 
@@ -287,7 +287,7 @@
    addressed by its arguments is the same and is updated in time for
    the rest of the program.
    This attribute is safe for a function that is effectless and idempotent; see
-   ISO C 23 § 6.7.12.7 for a definition of these terms.
+   ISO C 23 § 6.7.13.8 for a definition of these terms.
    (This attribute is looser than UNSEQUENCED because the function need
    not be stateless and idempotent.  It is looser than ATTRIBUTE_PURE
    because the function need not return exactly once and can affect
@@ -295,7 +295,7 @@
    See also <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2956.htm> and
    <https://stackoverflow.com/questions/76847905/>.
    ATTENTION! Efforts are underway to change the meaning of this attribute.
-   See <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3424.htm>.  */
+   See <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3494.htm>.  */
 /* Applies to: functions, pointer to functions, function type.  */
 #define REPRODUCIBLE _GL_ATTRIBUTE_REPRODUCIBLE
 
diff --git a/lib/dup2.c b/lib/dup2.c
index 69b37196dee..434e78c2bc6 100644
--- a/lib/dup2.c
+++ b/lib/dup2.c
@@ -114,10 +114,10 @@ klibc_dup2dirfd (int fd, int desired_fd)
   int dupfd;
 
   tempfd = open ("NUL", O_RDONLY);
-  if (tempfd == -1)
-    return -1;
+  if (tempfd < 0)
+    return tempfd;
 
-  if (tempfd == desired_fd)
+  if (tempfd >= desired_fd)
     {
       close (tempfd);
 
@@ -125,7 +125,29 @@ klibc_dup2dirfd (int fd, int desired_fd)
       if (__libc_Back_ioFHToPath (fd, path, sizeof (path)))
         return -1;
 
-      return open(path, O_RDONLY);
+      for (;;)
+        {
+          close (desired_fd);
+
+          dupfd = open (path, O_RDONLY);
+          if (dupfd < 0)
+            return dupfd;
+
+          if (dupfd == desired_fd)
+            return dupfd;
+
+          /* If lower FD was closed by other threads, fill again.  */
+          if (dupfd < desired_fd)
+            {
+              tempfd = dupfd;
+              break;
+            }
+
+          /* desired_fd was opened by other threads. Try again.  */
+          /* FIXME: Closing desired_fd opened by other threads may lead to
+             unexpected behavior.  */
+          close (dupfd);
+        }
     }
 
   dupfd = klibc_dup2dirfd (fd, desired_fd);
@@ -142,13 +164,9 @@ klibc_dup2 (int fd, int desired_fd)
   struct stat sbuf;
 
   dupfd = dup2 (fd, desired_fd);
-  if (dupfd == -1 && errno == ENOTSUP \
+  if (dupfd < 0 && errno == ENOTSUP \
       && !fstat (fd, &sbuf) && S_ISDIR (sbuf.st_mode))
-    {
-      close (desired_fd);
-
-      return klibc_dup2dirfd (fd, desired_fd);
-    }
+    return klibc_dup2dirfd (fd, desired_fd);
 
   return dupfd;
 }
@@ -179,10 +197,11 @@ rpl_dup2 (int fd, int desired_fd)
   result = dup2 (fd, desired_fd);
 
   /* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x.  */
-  if (result == -1 && errno == EMFILE)
+  if (result < 0 && errno == EMFILE)
     errno = EBADF;
+
 #if REPLACE_FCHDIR
-  if (fd != desired_fd && result != -1)
+  if (! (result < 0 || fd == desired_fd))
     result = _gl_register_dup (fd, result);
 #endif
   return result;
diff --git a/lib/fchmodat.c b/lib/fchmodat.c
index 9151778b8e3..4aa764f8510 100644
--- a/lib/fchmodat.c
+++ b/lib/fchmodat.c
@@ -46,7 +46,7 @@ orig_fchmodat (int dir, char const *file, mode_t mode, int flags)
 
 #include <intprops.h>
 
-#include "issymlink.h"
+#include "issymlinkat.h"
 
 /* Invoke chmod or lchmod on FILE, using mode MODE, in the directory
    open on descriptor FD.  If possible, do it without changing the
diff --git a/lib/fcntl.c b/lib/fcntl.c
index 29cb4f9eb84..abdd7b89890 100644
--- a/lib/fcntl.c
+++ b/lib/fcntl.c
@@ -29,8 +29,8 @@
 #include <unistd.h>
 
 #ifdef __KLIBC__
-# define INCL_DOS
-# include <os2.h>
+# include <emx/io.h>
+# include <InnoTekLIBC/backend.h>
 #endif
 
 #if defined _WIN32 && ! defined __CYGWIN__
@@ -539,6 +539,41 @@ rpl_fcntl_DUPFD_CLOEXEC (int fd, int target)
 #undef fcntl
 
 #ifdef __KLIBC__
+static int
+klibc_dupdirfd (int fd, int minfd)
+{
+  int tempfd;
+  int dupfd;
+
+  tempfd = open ("NUL", O_RDONLY);
+  if (tempfd == -1)
+    return -1;
+
+  if (tempfd >= minfd)
+    {
+      close (tempfd);
+
+      char path[_MAX_PATH];
+      if (__libc_Back_ioFHToPath (fd, path, sizeof (path)))
+        return -1;
+
+      dupfd = open (path, O_RDONLY);
+      if (dupfd == -1)
+        return -1;
+
+      if (dupfd >= minfd)
+        return dupfd;
+
+      /* Lower FD was closed by other threads. Fill again.  */
+      tempfd = dupfd;
+    }
+
+  dupfd = klibc_dupdirfd (fd, minfd);
+
+  close (tempfd);
+
+  return dupfd;
+}
 
 static int
 klibc_fcntl (int fd, int action, /* arg */...)
@@ -555,46 +590,50 @@ klibc_fcntl (int fd, int action, /* arg */...)
   if (result == -1 && (errno == EPERM || errno == ENOTSUP)
       && !fstat (fd, &sbuf) && S_ISDIR (sbuf.st_mode))
     {
-      ULONG ulMode;
+      PLIBCFH pFH;
+      unsigned fFlags;
 
       switch (action)
         {
         case F_DUPFD:
-          /* Find available fd */
-          while (fcntl (arg, F_GETFL) != -1 || errno != EBADF)
-            arg++;
-
-          result = dup2 (fd, arg);
+          result = klibc_dupdirfd (fd, arg);
           break;
 
-        /* Using underlying APIs is right ? */
         case F_GETFD:
-          if (DosQueryFHState (fd, &ulMode))
-            break;
+          pFH = __libc_FH (fd);
+          if (!pFH)
+            {
+              errno = EBADF;
+              break;
+            }
 
-          result = (ulMode & OPEN_FLAGS_NOINHERIT) ? FD_CLOEXEC : 0;
+          result = (pFH->fFlags & ((FD_CLOEXEC << __LIBC_FH_FDFLAGS_SHIFT )
+                                   | O_NOINHERIT)) ? FD_CLOEXEC : 0;
           break;
 
         case F_SETFD:
           if (arg & ~FD_CLOEXEC)
             break;
 
-          if (DosQueryFHState (fd, &ulMode))
-            break;
+          pFH = __libc_FH (fd);
+          if (!pFH)
+            {
+              errno = EBADF;
+              break;
+            }
 
+          fFlags = pFH->fFlags;
           if (arg & FD_CLOEXEC)
-            ulMode |= OPEN_FLAGS_NOINHERIT;
+            fFlags |= (FD_CLOEXEC << __LIBC_FH_FDFLAGS_SHIFT) | O_NOINHERIT;
           else
-            ulMode &= ~OPEN_FLAGS_NOINHERIT;
+            fFlags &= ~((FD_CLOEXEC << __LIBC_FH_FDFLAGS_SHIFT) | O_NOINHERIT);
 
-          /* Filter supported flags.  */
-          ulMode &= (OPEN_FLAGS_WRITE_THROUGH | OPEN_FLAGS_FAIL_ON_ERROR
-                     | OPEN_FLAGS_NO_CACHE | OPEN_FLAGS_NOINHERIT);
-
-          if (DosSetFHState (fd, ulMode))
-            break;
-
-          result = 0;
+          result = __libc_FHSetFlags (pFH, fd, fFlags);
+          if (result < 0)
+            {
+              errno = -result;
+              result = -1;
+            }
           break;
 
         case F_GETFL:
diff --git a/lib/file-has-acl.c b/lib/file-has-acl.c
index b1eb1f2e8e7..9a5a18aabcf 100644
--- a/lib/file-has-acl.c
+++ b/lib/file-has-acl.c
@@ -399,9 +399,9 @@ acl_get_link_np (char const *name, acl_type_t type)
   if (fd < 0)
     return NULL;
   acl_t r = acl_get_fd (fd);
-  int err = errno;
+  int saved_errno = errno;
   close (fd);
-  errno = err;
+  errno = saved_errno;
   return r;
 }
 #   define HAVE_ACL_GET_LINK_NP 1
diff --git a/lib/free.c b/lib/free.c
index 394d8d13905..3a6577f13fa 100644
--- a/lib/free.c
+++ b/lib/free.c
@@ -44,9 +44,9 @@ rpl_free (void *p)
   free (p);
   errno = err[errno == 0];
 # else
-  int err = errno;
+  int saved_errno = errno;
   free (p);
-  errno = err;
+  errno = saved_errno;
 # endif
 }
 
diff --git a/lib/getloadavg.c b/lib/getloadavg.c
index f9ed97b04bd..ec7305f5d48 100644
--- a/lib/getloadavg.c
+++ b/lib/getloadavg.c
@@ -551,11 +551,11 @@ getloadavg (double loadavg[], int nelem)
   if (fd < 0)
     return fd;
   int nread = read (fd, readbuf, sizeof readbuf - 1);
-  int err = errno;
+  int saved_errno = errno;
   close (fd);
   if (nread < 0)
     {
-      errno = err;
+      errno = saved_errno;
       return -1;
     }
   readbuf[nread] = '\0';
diff --git a/lib/gnulib.mk.in b/lib/gnulib.mk.in
index 96d9cd8bd44..297af181c57 100644
--- a/lib/gnulib.mk.in
+++ b/lib/gnulib.mk.in
@@ -71,6 +71,7 @@
 #  --avoid=stat \
 #  --avoid=std-gnu11 \
 #  --avoid=stdarg-h \
+#  --avoid=strncpy \
 #  --avoid=threadlib \
 #  --avoid=tzset \
 #  --avoid=unsetenv \
@@ -631,6 +632,7 @@ GL_GNULIB_STRERROR_R = @GL_GNULIB_STRERROR_R@
 GL_GNULIB_STRFTIME = @GL_GNULIB_STRFTIME@
 GL_GNULIB_STRINGEQ = @GL_GNULIB_STRINGEQ@
 GL_GNULIB_STRNCAT = @GL_GNULIB_STRNCAT@
+GL_GNULIB_STRNCPY = @GL_GNULIB_STRNCPY@
 GL_GNULIB_STRNDUP = @GL_GNULIB_STRNDUP@
 GL_GNULIB_STRNLEN = @GL_GNULIB_STRNLEN@
 GL_GNULIB_STRPBRK = @GL_GNULIB_STRPBRK@
@@ -1327,6 +1329,7 @@ REPLACE_STRERROR_L = @REPLACE_STRERROR_L@
 REPLACE_STRERROR_R = @REPLACE_STRERROR_R@
 REPLACE_STRFTIME = @REPLACE_STRFTIME@
 REPLACE_STRNCAT = @REPLACE_STRNCAT@
+REPLACE_STRNCPY = @REPLACE_STRNCPY@
 REPLACE_STRNDUP = @REPLACE_STRNDUP@
 REPLACE_STRNLEN = @REPLACE_STRNLEN@
 REPLACE_STRSIGNAL = @REPLACE_STRSIGNAL@
@@ -2650,7 +2653,7 @@ ifneq (,$(gl_GNULIB_ENABLED_issymlinkat_CONDITION))
 libgnu_a_SOURCES += issymlinkat.c
 
 endif
-EXTRA_DIST += issymlink.h
+EXTRA_DIST += issymlinkat.h
 
 endif
 ## end   gnulib module issymlinkat
@@ -3757,6 +3760,7 @@ string.h: string.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
               -e 's/@''GNULIB_STRDUP''@/$(GL_GNULIB_STRDUP)/g' \
               -e 's/@''GNULIB_STRINGEQ''@/$(GL_GNULIB_STRINGEQ)/g' \
               -e 's/@''GNULIB_STRNCAT''@/$(GL_GNULIB_STRNCAT)/g' \
+              -e 's/@''GNULIB_STRNCPY''@/$(GL_GNULIB_STRNCPY)/g' \
               -e 's/@''GNULIB_STRNDUP''@/$(GL_GNULIB_STRNDUP)/g' \
               -e 's/@''GNULIB_STRNLEN''@/$(GL_GNULIB_STRNLEN)/g' \
               -e 's/@''GNULIB_STRPBRK''@/$(GL_GNULIB_STRPBRK)/g' \
@@ -3818,6 +3822,7 @@ string.h: string.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
               -e 's|@''REPLACE_STRCHRNUL''@|$(REPLACE_STRCHRNUL)|g' \
               -e 's|@''REPLACE_STRDUP''@|$(REPLACE_STRDUP)|g' \
               -e 's|@''REPLACE_STRNCAT''@|$(REPLACE_STRNCAT)|g' \
+              -e 's|@''REPLACE_STRNCPY''@|$(REPLACE_STRNCPY)|g' \
               -e 's|@''REPLACE_STRNDUP''@|$(REPLACE_STRNDUP)|g' \
               -e 's|@''REPLACE_STRNLEN''@|$(REPLACE_STRNLEN)|g' \
               -e 's|@''REPLACE_STRSTR''@|$(REPLACE_STRSTR)|g' \
diff --git a/lib/issymlink.h b/lib/issymlink.h
index af6dc965645..a3f97cb5211 100644
--- a/lib/issymlink.h
+++ b/lib/issymlink.h
@@ -23,7 +23,7 @@
 #endif
 
 #include <errno.h>
-#include <unistd.h> /* for readlink, readlinkat */
+#include <unistd.h> /* for readlink */
 
 
 _GL_INLINE_HEADER_BEGIN
@@ -31,11 +31,7 @@ _GL_INLINE_HEADER_BEGIN
 #ifndef _GL_ISSYMLINK_INLINE
 # define _GL_ISSYMLINK_INLINE _GL_INLINE
 #endif
-#ifndef _GL_ISSYMLINKAT_INLINE
-# define _GL_ISSYMLINKAT_INLINE _GL_INLINE
-#endif
 
-#if GNULIB_ISSYMLINK
 /* Tests whether FILENAME represents a symbolic link.
    This function is more reliable than lstat() / fstatat() followed by S_ISLNK,
    because it avoids possible EOVERFLOW errors.
@@ -44,9 +40,9 @@ _GL_INLINE_HEADER_BEGIN
      0                      if FILENAME exists and is not a symbolic link,
     -1 with errno set       if determination failed, in particular
     -1 with errno = ENOENT or ENOTDIR  if FILENAME does not exist.  */
-# ifdef __cplusplus
+#ifdef __cplusplus
 extern "C" {
-# endif
+#endif
 _GL_ISSYMLINK_INLINE int issymlink (const char *filename)
      _GL_ARG_NONNULL ((1));
 _GL_ISSYMLINK_INLINE int
@@ -60,42 +56,8 @@ issymlink (const char *filename)
   else
     return -1;
 }
-# ifdef __cplusplus
-}
-# endif
-#endif
-
-#if GNULIB_ISSYMLINKAT
-/* Tests whether FILENAME represents a symbolic link.
-   This function is more reliable than lstat() / fstatat() followed by S_ISLNK,
-   because it avoids possible EOVERFLOW errors.
-   If FILENAME is a relative file name, it is interpreted as relative to the
-   directory referred to by FD (where FD = AT_FDCWD denotes the current
-   directory).
-   Returns
-     1                      if FILENAME is a symbolic link,
-     0                      if FILENAME exists and is not a symbolic link,
-    -1 with errno set       if determination failed, in particular
-    -1 with errno = ENOENT or ENOTDIR  if FILENAME does not exist.  */
-# ifdef __cplusplus
-extern "C" {
-# endif
-_GL_ISSYMLINKAT_INLINE int issymlinkat (int fd, const char *filename)
-     _GL_ARG_NONNULL ((2));
-_GL_ISSYMLINKAT_INLINE int
-issymlinkat (int fd, const char *filename)
-{
-  char linkbuf[1];
-  if (readlinkat (fd, filename, linkbuf, sizeof (linkbuf)) >= 0)
-    return 1;
-  if (errno == EINVAL)
-    return 0;
-  else
-    return -1;
-}
-# ifdef __cplusplus
+#ifdef __cplusplus
 }
-# endif
 #endif
 
 _GL_INLINE_HEADER_END
diff --git a/lib/issymlinkat.c b/lib/issymlinkat.c
index 8286356c8a2..ebd937e91bc 100644
--- a/lib/issymlinkat.c
+++ b/lib/issymlinkat.c
@@ -17,4 +17,4 @@
 #include <config.h>
 
 #define _GL_ISSYMLINKAT_INLINE _GL_EXTERN_INLINE
-#include "issymlink.h"
+#include "issymlinkat.h"
diff --git a/lib/issymlinkat.h b/lib/issymlinkat.h
new file mode 100644
index 00000000000..abbbbfff837
--- /dev/null
+++ b/lib/issymlinkat.h
@@ -0,0 +1,68 @@
+/* Test whether a file is a symbolic link.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#ifndef _ISSYMLINKAT_H
+#define _ISSYMLINKAT_H
+
+/* This file uses _GL_ARG_NONNULL, _GL_INLINE.  */
+#if !_GL_CONFIG_H_INCLUDED
+ #error "Please include config.h first."
+#endif
+
+#include <errno.h>
+#include <unistd.h> /* for readlinkat */
+
+
+_GL_INLINE_HEADER_BEGIN
+
+#ifndef _GL_ISSYMLINKAT_INLINE
+# define _GL_ISSYMLINKAT_INLINE _GL_INLINE
+#endif
+
+/* Tests whether FILENAME represents a symbolic link.
+   This function is more reliable than lstat() / fstatat() followed by S_ISLNK,
+   because it avoids possible EOVERFLOW errors.
+   If FILENAME is a relative file name, it is interpreted as relative to the
+   directory referred to by FD (where FD = AT_FDCWD denotes the current
+   directory).
+   Returns
+     1                      if FILENAME is a symbolic link,
+     0                      if FILENAME exists and is not a symbolic link,
+    -1 with errno set       if determination failed, in particular
+    -1 with errno = ENOENT or ENOTDIR  if FILENAME does not exist.  */
+#ifdef __cplusplus
+extern "C" {
+#endif
+_GL_ISSYMLINKAT_INLINE int issymlinkat (int fd, const char *filename)
+     _GL_ARG_NONNULL ((2));
+_GL_ISSYMLINKAT_INLINE int
+issymlinkat (int fd, const char *filename)
+{
+  char linkbuf[1];
+  if (readlinkat (fd, filename, linkbuf, sizeof (linkbuf)) >= 0)
+    return 1;
+  if (errno == EINVAL)
+    return 0;
+  else
+    return -1;
+}
+#ifdef __cplusplus
+}
+#endif
+
+_GL_INLINE_HEADER_END
+
+#endif /* _ISSYMLINKAT_H */
diff --git a/lib/lchmod.c b/lib/lchmod.c
index deba4c50f5b..acccef629cc 100644
--- a/lib/lchmod.c
+++ b/lib/lchmod.c
@@ -30,6 +30,7 @@
 
 #include <intprops.h>
 #include "issymlink.h"
+#include "issymlinkat.h"
 
 /* Work like chmod, except when FILE is a symbolic link.
    In that case, on systems where permissions on symbolic links are unsupported
diff --git a/lib/realloc.c b/lib/realloc.c
index 62efd5a39ff..cf0bf6e9f70 100644
--- a/lib/realloc.c
+++ b/lib/realloc.c
@@ -94,7 +94,7 @@ rpl_realloc (void *p, size_t n)
 
   void *result = realloc (p, n1);
 
-# if !HAVE_MALLOC_POSIX
+# if !HAVE_REALLOC_POSIX
   if (result == NULL)
     errno = ENOMEM;
 # endif
diff --git a/lib/str-two-way.h b/lib/str-two-way.h
index 852e5d078f2..1da773eb70e 100644
--- a/lib/str-two-way.h
+++ b/lib/str-two-way.h
@@ -374,32 +374,34 @@ two_way_long_needle (const unsigned char *haystack, size_t haystack_len,
                 }
               memory = 0;
               j += shift;
-              continue;
-            }
-          /* Scan for matches in right half.  The last byte has
-             already been matched, by virtue of the shift table.  */
-          size_t i = MAX (suffix, memory);
-          while (i < needle_len - 1 && (CANON_ELEMENT (needle[i])
-                                        == CANON_ELEMENT (haystack[i + j])))
-            ++i;
-          if (needle_len - 1 <= i)
-            {
-              /* Scan for matches in left half.  */
-              i = suffix - 1;
-              while (memory < i + 1 && (CANON_ELEMENT (needle[i])
-                                        == CANON_ELEMENT (haystack[i + j])))
-                --i;
-              if (i + 1 < memory + 1)
-                return (RETURN_TYPE) (haystack + j);
-              /* No match, so remember how many repetitions of period
-                 on the right half were scanned.  */
-              j += period;
-              memory = needle_len - period;
             }
           else
             {
-              j += i - suffix + 1;
-              memory = 0;
+              /* Scan for matches in right half.  The last byte has
+                 already been matched, by virtue of the shift table.  */
+              size_t i = MAX (suffix, memory);
+              while (i < needle_len - 1 && (CANON_ELEMENT (needle[i])
+                                            == CANON_ELEMENT (haystack[i + j])))
+                ++i;
+              if (needle_len - 1 <= i)
+                {
+                  /* Scan for matches in left half.  */
+                  i = suffix - 1;
+                  while (memory < i + 1 && (CANON_ELEMENT (needle[i])
+                                            == CANON_ELEMENT (haystack[i + j])))
+                    --i;
+                  if (i + 1 < memory + 1)
+                    return (RETURN_TYPE) (haystack + j);
+                  /* No match, so remember how many repetitions of period
+                     on the right half were scanned.  */
+                  j += period;
+                  memory = needle_len - period;
+                }
+              else
+                {
+                  j += i - suffix + 1;
+                  memory = 0;
+                }
             }
         }
     }
@@ -418,27 +420,29 @@ two_way_long_needle (const unsigned char *haystack, size_t haystack_len,
           if (0 < shift)
             {
               j += shift;
-              continue;
             }
-          /* Scan for matches in right half.  The last byte has
-             already been matched, by virtue of the shift table.  */
-          size_t i = suffix;
-          while (i < needle_len - 1 && (CANON_ELEMENT (needle[i])
-                                        == CANON_ELEMENT (haystack[i + j])))
-            ++i;
-          if (needle_len - 1 <= i)
+          else
             {
-              /* Scan for matches in left half.  */
-              i = suffix - 1;
-              while (i != SIZE_MAX && (CANON_ELEMENT (needle[i])
-                                       == CANON_ELEMENT (haystack[i + j])))
-                --i;
-              if (i == SIZE_MAX)
-                return (RETURN_TYPE) (haystack + j);
-              j += period;
+              /* Scan for matches in right half.  The last byte has
+                 already been matched, by virtue of the shift table.  */
+              size_t i = suffix;
+              while (i < needle_len - 1 && (CANON_ELEMENT (needle[i])
+                                            == CANON_ELEMENT (haystack[i + j])))
+                ++i;
+              if (needle_len - 1 <= i)
+                {
+                  /* Scan for matches in left half.  */
+                  i = suffix - 1;
+                  while (i != SIZE_MAX && (CANON_ELEMENT (needle[i])
+                                           == CANON_ELEMENT (haystack[i + j])))
+                    --i;
+                  if (i == SIZE_MAX)
+                    return (RETURN_TYPE) (haystack + j);
+                  j += period;
+                }
+              else
+                j += i - suffix + 1;
             }
-          else
-            j += i - suffix + 1;
         }
     }
   return NULL;
diff --git a/lib/string.in.h b/lib/string.in.h
index a323b1cd6da..f316878b4c9 100644
--- a/lib/string.in.h
+++ b/lib/string.in.h
@@ -840,6 +840,35 @@ _GL_WARN_ON_USE (strncat, "strncat is unportable - "
 # endif
 #endif
 
+/* Copy no more than N bytes of SRC to DST, returning DST.  */
+#if @GNULIB_STRNCPY@
+# if @REPLACE_STRNCPY@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef strncpy
+#   define strncpy rpl_strncpy
+#  endif
+_GL_FUNCDECL_RPL (strncpy, char *,
+                  (char *restrict __dst, char const *restrict __src,
+                   size_t __n),
+                  _GL_ARG_NONNULL ((1, 2)));
+_GL_CXXALIAS_RPL (strncpy, char *,
+                  (char *restrict __dst, char const *restrict __src,
+                   size_t __n));
+# else
+_GL_CXXALIAS_SYS (strncpy, char *,
+                  (char *restrict __dst, char const *restrict __src,
+                   size_t __n));
+# endif
+# if __GLIBC__ >= 2
+_GL_CXXALIASWARN (strncpy);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# if HAVE_RAW_DECL_STRNCPY
+_GL_WARN_ON_USE (strncpy, "strncpy is unportable - "
+                 "use gnulib module strncpy for portability");
+# endif
+#endif
+
 /* Return a newly allocated copy of at most N bytes of STRING.  */
 #if @GNULIB_STRNDUP@
 # if @REPLACE_STRNDUP@
diff --git a/lib/time_rz.c b/lib/time_rz.c
index 8a8eb44c357..116ac39ad2d 100644
--- a/lib/time_rz.c
+++ b/lib/time_rz.c
@@ -57,9 +57,9 @@ void
 tzfree (timezone_t tz)
 # undef tzfree
 {
-  int err = errno;
+  int saved_errno = errno;
   tzfree (tz);
-  errno = err;
+  errno = saved_errno;
 }
 
 #else