diff -ruN a/lib/backupfile.c b/lib/backupfile.c
--- a/lib/backupfile.c	2026-03-27 15:38:11
+++ b/lib/backupfile.c	2026-03-27 15:39:04
@@ -214,9 +214,18 @@
   idx_t versionlenmax = 1;
   idx_t baselen = filelen - base_offset;
 
+#ifdef _WIN32
   if (dirp)
+    {
+      closedir (dirp);
+      dirp = NULL;
+      *dirpp = NULL;
+    }
+#else
+  if (dirp)
     rewinddir (dirp);
   else
+#endif
     {
       /* Temporarily modify the buffer into its parent directory name,
          open the directory, and then restore the buffer.  */
diff -ruN a/src/pch.c b/src/pch.c
--- a/src/pch.c	2026-03-27 15:38:11
+++ b/src/pch.c	2026-03-27 15:38:15
@@ -352,7 +352,9 @@
       uses zero to indicate unknown or missing file types, S_IFLNK and
       S_IFREG must be nonzero.  This is true on all known platforms
       although POSIX does not require it; check here to be sure.  */
+#ifdef S_IFLNK
    static_assert (S_IFLNK);
+#endif
    static_assert (S_IFREG);
 
    mode_t m = file_type | (mode & S_IRWXUGO);
diff -ruN a/src/safe.c b/src/safe.c
--- a/src/safe.c	2026-03-27 15:38:11
+++ b/src/safe.c	2026-03-27 15:38:31
@@ -21,7 +21,13 @@
 #include <config.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#ifdef _WIN32
+# include <limits.h>
+typedef unsigned long int rlim_t;
+# define RLIM_INFINITY ULONG_MAX
+#else
 #include <sys/resource.h>
+#endif
 #include <sys/time.h>
 #include <fcntl.h>
 #include <stdio.h>
@@ -103,6 +109,7 @@
 
 static void init_dirfd_cache (void)
 {
+#ifndef _WIN32
   struct rlimit nofile;
 
   if (getrlimit (RLIMIT_NOFILE, &nofile) == 0)
@@ -113,6 +120,7 @@
 	max_cached_fds = MAX (nofile.rlim_cur / 4, min_cached_fds);
     }
   else
+#endif
     max_cached_fds = min_cached_fds;
 
   cached_dirfds = hash_initialize (min_cached_fds, nullptr,
@@ -686,6 +694,7 @@
   return fchmodat (dirfd, pathname, mode, 0);
 }
 
+#ifndef _WIN32
 /* Replacement for lchown() */
 int
 safe_lchown (char *pathname, uid_t owner, gid_t group)
@@ -695,6 +704,7 @@
     return -1;
   return fchownat (dirfd, pathname, owner, group, AT_SYMLINK_NOFOLLOW);
 }
+#endif
 
 /* Replacement for lutimens() */
 int
diff -ruN a/src/safe.h b/src/safe.h
--- a/src/safe.h	2026-03-27 15:38:11
+++ b/src/safe.h	2026-03-27 15:38:16
@@ -36,7 +36,9 @@
 int safe_unlink (char *pathname);
 int safe_symlink (const char *target, char *linkpath);
 int safe_chmod (char *pathname, mode_t mode);
+#ifndef _WIN32
 int safe_lchown (char *pathname, uid_t owner, gid_t group);
+#endif
 int safe_lutimens (char *pathname, struct timespec const times[2]);
 ssize_t safe_readlink(char *pathname, char *buf, size_t bufsiz);
 int safe_access(char *pathname, int mode);
diff -ruN a/src/util.c b/src/util.c
--- a/src/util.c	2026-03-27 15:38:11
+++ b/src/util.c	2026-03-27 15:38:56
@@ -315,6 +315,7 @@
 	pfatal ("Failed to set the timestamps of %s %s",
 		S_ISLNK (mode) ? "symbolic link" : "file",
 		quotearg (to));
+#ifndef _WIN32
     }
   if (attr & FA_IDS)
     {
@@ -350,6 +351,7 @@
 		uid == uid_1 ? "owner" : "owning group",
 		S_ISLNK (mode) ? "symbolic link" : "file",
 		quotearg (to));
+#endif
     }
   if (attr & FA_XATTRS)
     if (copy_attr (from, fromfd, to, tofd) < 0
@@ -362,7 +364,11 @@
 	 symlinks, so don't try to set symlink file permissions even on
 	 systems where we could.  */
       if (! S_ISLNK (mode)
+#ifdef _WIN32
+	  && safe_chmod (to, mode) < 0)
+#else
 	  && (tofd < 0 ? safe_chmod (to, mode) : fchmod (tofd, mode)) < 0)
+#endif
 	pfatal ("Failed to set the permissions of %s %s",
 		S_ISLNK (mode) ? "symbolic link" : "file",
 		quotearg (to));
@@ -1228,7 +1234,9 @@
 {
   static int const sigs[] =
     {
+#ifdef SIGHUP
       SIGHUP,
+#endif
       SIGINT,
 #ifdef SIGPIPE
       SIGPIPE,
@@ -1246,7 +1254,9 @@
   enum { NUM_SIGS = sizeof sigs / sizeof *sigs };
 
   /* System V fork+wait does not work if SIGCHLD is ignored.  */
+#ifdef SIGCHLD
   signal (SIGCHLD, SIG_DFL);
+#endif
 
 #if HAVE_SIGACTION && HAVE_SIGFILLSET
   struct sigaction fatal_act = { .sa_handler = handle_signal };