diff --git a/ChangeLog b/ChangeLog
index 357763722a..a256b809e7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2020-02-10  Bruno Haible  <bruno@clisp.org>
+
+	pthread-mutex-tests, pthread-rwlock-tests: Fix link errors on HP-UX.
+	* modules/pthread-mutex-tests (Makefile.am): Link test-pthread-mutex
+	with $(LIB_SEMAPHORE).
+	* modules/pthread-rwlock-tests (Makefile.am): Link test-pthread-rwlock
+	with $(LIB_SEMAPHORE).
+
 2020-02-10  Bruno Haible  <bruno@clisp.org>
 
 	ptsname_r-tests: Avoid unused function warning.
diff --git a/modules/pthread-mutex-tests b/modules/pthread-mutex-tests
index eb6ec7bea8..12d386e63f 100644
--- a/modules/pthread-mutex-tests
+++ b/modules/pthread-mutex-tests
@@ -11,4 +11,4 @@ configure.ac:
 Makefile.am:
 TESTS += test-pthread-mutex
 check_PROGRAMS += test-pthread-mutex
-test_pthread_mutex_LDADD = $(LDADD) @LIBPMULTITHREAD@ @LIB_SCHED_YIELD@
+test_pthread_mutex_LDADD = $(LDADD) @LIBPMULTITHREAD@ @LIB_SCHED_YIELD@ @LIB_SEMAPHORE@
diff --git a/modules/pthread-rwlock-tests b/modules/pthread-rwlock-tests
index 7f35198e87..340ebf0afe 100644
--- a/modules/pthread-rwlock-tests
+++ b/modules/pthread-rwlock-tests
@@ -12,4 +12,4 @@ configure.ac:
 Makefile.am:
 TESTS += test-pthread-rwlock
 check_PROGRAMS += test-pthread-rwlock
-test_pthread_rwlock_LDADD = $(LDADD) @LIBPMULTITHREAD@ @LIB_SCHED_YIELD@
+test_pthread_rwlock_LDADD = $(LDADD) @LIBPMULTITHREAD@ @LIB_SCHED_YIELD@ @LIB_SEMAPHORE@