diff --git a/ChangeLog b/ChangeLog
index 188bb8f2f..69d41bf1a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,28 @@
+2020-09-23  Tim Rice  <tim@multitalents.net>
+
+	* tests/nap.h: rename to tests/gnulib_nap.h
+	* tests/gnulib_nap.h: avoid name space clash with UniWare's libc.
+	  rename nap() to gnulib_nap(). nap() dates back to Xenix 286.
+	  First discussed here
+	  <https://lists.gnu.org/archive/html/bug-gnulib/2020-02/msg00025.html>
+	* modules/chown-tests: Likewise
+	* modules/fchownat-tests: Likewise
+	* modules/fdutimensat-tests: Likewise
+	* modules/futimens-tests: Likewise
+	* modules/lchown-tests: Likewise
+	* modules/stat-time-tests: Likewise
+	* modules/utime-tests: Likewise
+	* modules/utimens-tests: Likewise
+	* modules/utimensat-tests: Likewise
+	* tests/test-chown.h: Likewise
+	* tests/test-futimens.h: Likewise
+	* tests/test-lchown.h: Likewise
+	* tests/test-lutimens.h: Likewise
+	* tests/test-stat-time.c: Likewise
+	* tests/test-utime.c: Likewise
+	* tests/test-utimens.h: Likewise
+	* tests/test-utimens-common.h
+
 2020-09-20  Norihiro Tanaka  <noritnk@kcn.ne.jp>
 
 	dfa: make dfasupported a global function
diff --git a/modules/chown-tests b/modules/chown-tests
index 13138f438..33f730daa 100644
--- a/modules/chown-tests
+++ b/modules/chown-tests
@@ -1,5 +1,5 @@
 Files:
-tests/nap.h
+tests/gnulib_nap.h
 tests/test-chown.h
 tests/test-chown.c
 tests/signature.h
diff --git a/modules/fchownat-tests b/modules/fchownat-tests
index e5fb7833f..62f6f4a1d 100644
--- a/modules/fchownat-tests
+++ b/modules/fchownat-tests
@@ -1,5 +1,5 @@
 Files:
-tests/nap.h
+tests/gnulib_nap.h
 tests/test-chown.h
 tests/test-lchown.h
 tests/test-fchownat.c
diff --git a/modules/fdutimensat-tests b/modules/fdutimensat-tests
index 37f70c652..0ee034a9b 100644
--- a/modules/fdutimensat-tests
+++ b/modules/fdutimensat-tests
@@ -1,5 +1,5 @@
 Files:
-tests/nap.h
+tests/gnulib_nap.h
 tests/test-futimens.h
 tests/test-lutimens.h
 tests/test-utimens.h
diff --git a/modules/futimens-tests b/modules/futimens-tests
index 519141300..2116246d9 100644
--- a/modules/futimens-tests
+++ b/modules/futimens-tests
@@ -1,5 +1,5 @@
 Files:
-tests/nap.h
+tests/gnulib_nap.h
 tests/test-futimens.h
 tests/test-utimens-common.h
 tests/test-futimens.c
diff --git a/modules/lchown-tests b/modules/lchown-tests
index 42b946014..004cda60f 100644
--- a/modules/lchown-tests
+++ b/modules/lchown-tests
@@ -1,5 +1,5 @@
 Files:
-tests/nap.h
+tests/gnulib_nap.h
 tests/test-lchown.h
 tests/test-lchown.c
 tests/signature.h
diff --git a/modules/stat-time-tests b/modules/stat-time-tests
index c512eca76..3c14de2f9 100644
--- a/modules/stat-time-tests
+++ b/modules/stat-time-tests
@@ -1,7 +1,7 @@
 Files:
 tests/test-stat-time.c
 tests/macros.h
-tests/nap.h
+tests/gnulib_nap.h
 
 Depends-on:
 intprops
diff --git a/modules/utime-tests b/modules/utime-tests
index a64d0a006..a01546cdc 100644
--- a/modules/utime-tests
+++ b/modules/utime-tests
@@ -1,6 +1,6 @@
 Files:
 tests/test-utime.c
-tests/nap.h
+tests/gnulib_nap.h
 tests/test-utimens-common.h
 tests/macros.h
 
diff --git a/modules/utimens-tests b/modules/utimens-tests
index 2a95346a0..28ebadae3 100644
--- a/modules/utimens-tests
+++ b/modules/utimens-tests
@@ -1,5 +1,5 @@
 Files:
-tests/nap.h
+tests/gnulib_nap.h
 tests/test-futimens.h
 tests/test-lutimens.h
 tests/test-utimens.h
diff --git a/modules/utimensat-tests b/modules/utimensat-tests
index 15c79407e..86d2ac2de 100644
--- a/modules/utimensat-tests
+++ b/modules/utimensat-tests
@@ -1,5 +1,5 @@
 Files:
-tests/nap.h
+tests/gnulib_nap.h
 tests/test-lutimens.h
 tests/test-utimens.h
 tests/test-utimens-common.h
diff --git a/tests/gnulib_nap.h b/tests/gnulib_nap.h
index 5dd264f6d..784c22f07 100644
--- a/tests/gnulib_nap.h
+++ b/tests/gnulib_nap.h
@@ -25,7 +25,7 @@
 # include <intprops.h>
 
 /* Name of the witness file.  */
-#define TEMPFILE BASE "nap.tmp"
+#define TEMPFILE BASE "gnulib_nap.tmp"
 
 /* File descriptor used for the witness file.  */
 static int nap_fd = -1;
@@ -114,7 +114,7 @@ clear_temp_file (void)
    Assumes that BASE is defined, and requires that the test module
    depends on nanosleep.  */
 static void
-nap (void)
+gnulib_nap (void)
 {
   struct stat old_st;
   static int delay = 1;
diff --git a/tests/test-chown.h b/tests/test-chown.h
index eb068f0b8..5863dfea3 100644
--- a/tests/test-chown.h
+++ b/tests/test-chown.h
@@ -16,7 +16,7 @@
 
 /* Written by Eric Blake <ebb9@byu.net>, 2009.  */
 
-#include "nap.h"
+#include "gnulib_nap.h"
 
 #if !HAVE_GETEGID
 # define getegid() ((gid_t) -1)
@@ -98,7 +98,7 @@ test_chown (int (*func) (char const *, uid_t, gid_t), bool print)
 
   /* Even if the values aren't changing, ctime is required to change
      if at least one argument is not -1.  */
-  nap ();
+  gnulib_nap ();
   ASSERT (func (BASE "dir/file", st1.st_uid, st1.st_gid) == 0);
   ASSERT (stat (BASE "dir/file", &st2) == 0);
   ASSERT (st1.st_ctime < st2.st_ctime
@@ -172,7 +172,7 @@ test_chown (int (*func) (char const *, uid_t, gid_t), bool print)
       ASSERT (lstat (BASE "dir/link", &l1) == 0);
       ASSERT (lstat (BASE "dir/link2", &l2) == 0);
 
-      nap ();
+      gnulib_nap ();
       errno = 0;
       ASSERT (func (BASE "dir/link2/", -1, st1.st_gid) == -1);
       ASSERT (errno == ENOTDIR);
diff --git a/tests/test-futimens.h b/tests/test-futimens.h
index b5645e6d1..bbac0db04 100644
--- a/tests/test-futimens.h
+++ b/tests/test-futimens.h
@@ -32,7 +32,7 @@ test_futimens (int (*func) (int, struct timespec const *),
 
   /* Sanity check.  */
   ASSERT (fstat (fd, &st1) == 0);
-  nap ();
+  gnulib_nap ();
   errno = 0;
   result = func (fd, NULL);
   if (result == -1 && errno == ENOSYS)
@@ -68,7 +68,7 @@ test_futimens (int (*func) (int, struct timespec const *),
     ts[1] = ts[0];
     ASSERT (func (fd, ts) == 0);
     ASSERT (fstat (fd, &st1) == 0);
-    nap ();
+    gnulib_nap ();
   }
 
   /* Invalid arguments.  */
@@ -148,7 +148,7 @@ test_futimens (int (*func) (int, struct timespec const *),
     ts[0].tv_nsec = UTIME_OMIT;
     ts[1].tv_sec = 0;
     ts[1].tv_nsec = UTIME_NOW;
-    nap ();
+    gnulib_nap ();
     ASSERT (func (fd, ts) == 0);
     ASSERT (fstat (fd, &st3) == 0);
     ASSERT (st3.st_atime == Y2K);
@@ -157,7 +157,7 @@ test_futimens (int (*func) (int, struct timespec const *),
     ASSERT (utimecmp (BASE "file", &st1, &st3, 0) <= 0);
     if (check_ctime)
       ASSERT (ctime_compare (&st2, &st3) < 0);
-    nap ();
+    gnulib_nap ();
     ts[0].tv_nsec = 0;
     ts[1].tv_nsec = UTIME_OMIT;
     ASSERT (func (fd, ts) == 0);
diff --git a/tests/test-lchown.h b/tests/test-lchown.h
index cf29e29c4..bcbe182f0 100644
--- a/tests/test-lchown.h
+++ b/tests/test-lchown.h
@@ -16,7 +16,7 @@
 
 /* Written by Eric Blake <ebb9@byu.net>, 2009.  */
 
-#include "nap.h"
+#include "gnulib_nap.h"
 
 #if !HAVE_GETEGID
 # define getegid() ((gid_t) -1)
@@ -106,7 +106,7 @@ test_lchown (int (*func) (char const *, uid_t, gid_t), bool print)
 
   /* Even if the values aren't changing, ctime is required to change
      if at least one argument is not -1.  */
-  nap ();
+  gnulib_nap ();
   ASSERT (func (BASE "dir/file", st1.st_uid, st1.st_gid) == 0);
   ASSERT (stat (BASE "dir/file", &st2) == 0);
   ASSERT (st1.st_ctime < st2.st_ctime
@@ -208,7 +208,7 @@ test_lchown (int (*func) (char const *, uid_t, gid_t), bool print)
       ASSERT (lstat (BASE "dir/link", &l1) == 0);
       ASSERT (lstat (BASE "dir/link2", &l2) == 0);
 
-      nap ();
+      gnulib_nap ();
       errno = 0;
       ASSERT (func (BASE "dir/link2/", -1, st1.st_gid) == -1);
       ASSERT (errno == ENOTDIR);
@@ -237,7 +237,7 @@ test_lchown (int (*func) (char const *, uid_t, gid_t), bool print)
       /* Trailing slash follows through to directory.  */
       ASSERT (lstat (BASE "dir/sub", &st1) == 0);
       ASSERT (lstat (BASE "dir/link3", &l1) == 0);
-      nap ();
+      gnulib_nap ();
       ASSERT (func (BASE "dir/link3/", -1, st1.st_gid) == 0);
       ASSERT (lstat (BASE "dir/link3", &st2) == 0);
       ASSERT (l1.st_ctime == st2.st_ctime);
diff --git a/tests/test-lutimens.h b/tests/test-lutimens.h
index 90aa5141b..22e469ef0 100644
--- a/tests/test-lutimens.h
+++ b/tests/test-lutimens.h
@@ -60,7 +60,7 @@ test_lutimens (int (*func) (char const *, struct timespec const *), bool print)
     ts[0].tv_sec = Y2K;
     ts[0].tv_nsec = 0;
     ts[1] = ts[0];
-    nap ();
+    gnulib_nap ();
     ASSERT (func (BASE "file", ts) == 0);
   }
   ASSERT (stat (BASE "file", &st2) == 0);
@@ -102,7 +102,7 @@ test_lutimens (int (*func) (char const *, struct timespec const *), bool print)
   ASSERT (lstat (BASE "link", &st1) == 0);
   /* On cygwin, lstat() changes atime of symlinks, so that lutimens
      can only effectively modify mtime.  */
-  nap ();
+  gnulib_nap ();
   ASSERT (lstat (BASE "link", &st2) == 0);
   if (st1.st_atime != st2.st_atime
       || get_stat_atime_ns (&st1) != get_stat_atime_ns (&st2))
@@ -146,7 +146,7 @@ test_lutimens (int (*func) (char const *, struct timespec const *), bool print)
     ts[0].tv_nsec = BILLION / 2 - 1;
     ts[1].tv_sec = Y2K;
     ts[1].tv_nsec = BILLION - 1;
-    nap ();
+    gnulib_nap ();
     ASSERT (func (BASE "link", ts) == 0);
     ASSERT (lstat (BASE "link", &st2) == 0);
     if (atime_supported)
@@ -170,7 +170,7 @@ test_lutimens (int (*func) (char const *, struct timespec const *), bool print)
     ts[0].tv_nsec = UTIME_OMIT;
     ts[1].tv_sec = 0;
     ts[1].tv_nsec = UTIME_NOW;
-    nap ();
+    gnulib_nap ();
     ASSERT (func (BASE "link", ts) == 0);
     ASSERT (lstat (BASE "link", &st3) == 0);
     if (atime_supported)
@@ -182,7 +182,7 @@ test_lutimens (int (*func) (char const *, struct timespec const *), bool print)
     ASSERT (utimecmp (BASE "link", &st1, &st3, 0) <= 0);
     if (check_ctime)
       ASSERT (ctime_compare (&st2, &st3) < 0);
-    nap ();
+    gnulib_nap ();
     ts[0].tv_nsec = 0;
     ts[1].tv_nsec = UTIME_OMIT;
     ASSERT (func (BASE "link", ts) == 0);
diff --git a/tests/test-stat-time.c b/tests/test-stat-time.c
index 86d4346d9..09a3d0bb1 100644
--- a/tests/test-stat-time.c
+++ b/tests/test-stat-time.c
@@ -30,7 +30,7 @@
 #include "macros.h"
 
 #define BASE "test-stat-time.t"
-#include "nap.h"
+#include "gnulib_nap.h"
 
 enum { NFILES = 4 };
 
@@ -110,13 +110,13 @@ prepare_test (struct stat *statinfo, struct timespec *modtimes)
   int i;
 
   create_file (filename_stamp1);
-  nap ();
+  gnulib_nap ();
   create_file (filename_testfile);
-  nap ();
+  gnulib_nap ();
   create_file (filename_stamp2);
-  nap ();
+  gnulib_nap ();
   ASSERT (chmod (filename_testfile, 0400) == 0);
-  nap ();
+  gnulib_nap ();
   create_file (filename_stamp3);
 
   do_stat (filename_stamp1,   &statinfo[0]);
diff --git a/tests/test-utime.c b/tests/test-utime.c
index 4cf583606..1ee3de6eb 100644
--- a/tests/test-utime.c
+++ b/tests/test-utime.c
@@ -38,7 +38,7 @@ test_utime (bool print)
 
   ASSERT (close (creat (BASE "file", 0600)) == 0);
   ASSERT (stat (BASE "file", &st1) == 0);
-  nap ();
+  gnulib_nap ();
   ASSERT (utime (BASE "file", NULL) == 0);
   ASSERT (stat (BASE "file", &st2) == 0);
   ASSERT (0 <= utimecmp (BASE "file", &st2, &st1, UTIMECMP_TRUNCATE_SOURCE));
@@ -56,7 +56,7 @@ test_utime (bool print)
     ts.actime = ts.modtime = time (NULL);
     ASSERT (utime (BASE "file", &ts) == 0);
     ASSERT (stat (BASE "file", &st1) == 0);
-    nap ();
+    gnulib_nap ();
   }
 
   /* Invalid arguments.  */
diff --git a/tests/test-utimens-common.h b/tests/test-utimens-common.h
index e92362085..1df1fe7b7 100644
--- a/tests/test-utimens-common.h
+++ b/tests/test-utimens-common.h
@@ -31,7 +31,7 @@
 # include "utimecmp.h"
 
 /* Gnulib test header.  */
-# include "nap.h"
+# include "gnulib_nap.h"
 
 enum {
   BILLION = 1000 * 1000 * 1000,
diff --git a/tests/test-utimens.h b/tests/test-utimens.h
index a05b232a8..10aef0892 100644
--- a/tests/test-utimens.h
+++ b/tests/test-utimens.h
@@ -33,7 +33,7 @@ test_utimens (int (*func) (char const *, struct timespec const *), bool print)
      UTIMECMP_TRUNCATE_SOURCE to compensate, with st1 as the
      source.  */
   ASSERT (stat (BASE "file", &st1) == 0);
-  nap ();
+  gnulib_nap ();
   ASSERT (func (BASE "file", NULL) == 0);
   ASSERT (stat (BASE "file", &st2) == 0);
   ASSERT (0 <= utimecmp (BASE "file", &st2, &st1, UTIMECMP_TRUNCATE_SOURCE));
@@ -52,7 +52,7 @@ test_utimens (int (*func) (char const *, struct timespec const *), bool print)
     ts[1] = ts[0];
     ASSERT (func (BASE "file", ts) == 0);
     ASSERT (stat (BASE "file", &st1) == 0);
-    nap ();
+    gnulib_nap ();
   }
 
   /* Invalid arguments.  */
@@ -126,7 +126,7 @@ test_utimens (int (*func) (char const *, struct timespec const *), bool print)
     ts[0].tv_nsec = UTIME_OMIT;
     ts[1].tv_sec = 0;
     ts[1].tv_nsec = UTIME_NOW;
-    nap ();
+    gnulib_nap ();
     ASSERT (func (BASE "file", ts) == 0);
     ASSERT (stat (BASE "file", &st3) == 0);
     ASSERT (st3.st_atime == Y2K);
@@ -136,7 +136,7 @@ test_utimens (int (*func) (char const *, struct timespec const *), bool print)
     ASSERT (0 <= utimecmp (BASE "file", &st3, &st1, UTIMECMP_TRUNCATE_SOURCE));
     if (check_ctime)
       ASSERT (ctime_compare (&st2, &st3) < 0);
-    nap ();
+    gnulib_nap ();
     ts[0].tv_nsec = 0;
     ts[1].tv_nsec = UTIME_OMIT;
     ASSERT (func (BASE "file", ts) == 0);