diff --git a/cmake/check.cmake b/cmake/check.cmake
index e1ea471e8..83f3f5643 100644
--- a/cmake/check.cmake
+++ b/cmake/check.cmake
@@ -24,6 +24,12 @@ if (GALERA_HAVE_SUBUNIT_LIB)
   list(APPEND GALERA_UNIT_TEST_LIBS "${GALERA_HAVE_SUBUNIT_LIB}")
 endif()
 
+# needed on old systems with glibc < 2.17 for timer_create() in libcheck.
+find_library(RT_LIB rt)
+if (RT_LIB)
+  list(APPEND GALERA_UNIT_TEST_LIBS "${RT_LIB}")
+endif()
+
 list(APPEND GALERA_UNIT_TEST_LIBS m)
 list(APPEND GALERA_UNIT_TEST_LIBS ${GALERA_SYSTEM_LIBS})
 
diff --git a/cmake/os.cmake b/cmake/os.cmake
index 75d3a44d1..6d039a2c6 100644
--- a/cmake/os.cmake
+++ b/cmake/os.cmake
@@ -5,8 +5,8 @@
 #
 
 find_library(PTHREAD_LIB pthread)
-find_library(RT_LIB rt)
-set(GALERA_SYSTEM_LIBS ${PTHREAD_LIB} ${RT_LIB})
+
+set(GALERA_SYSTEM_LIBS ${PTHREAD_LIB})
 
 if (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
   # Check if linkage with atomic library is needed for 8 byte atomics
diff --git a/galerautils/tests/CMakeLists.txt b/galerautils/tests/CMakeLists.txt
index a44b2d6b3..36522a7d3 100644
--- a/galerautils/tests/CMakeLists.txt
+++ b/galerautils/tests/CMakeLists.txt
@@ -102,7 +102,7 @@ target_compile_options(deqmap_bench
   PRIVATE
   -Wno-conversion)
 
-target_link_libraries(deqmap_bench galerautilsxx rt)
+target_link_libraries(deqmap_bench galerautilsxx)
 
 #
 # CRC32C micro benchmark.
diff --git a/gcache/src/CMakeLists.txt b/gcache/src/CMakeLists.txt
index e518c89d1..f174f6b4d 100644
--- a/gcache/src/CMakeLists.txt
+++ b/gcache/src/CMakeLists.txt
@@ -33,7 +33,7 @@ target_link_libraries(gcache galerautilsxx)
 
 add_executable(gcache_test test.cpp)
 
-target_link_libraries(gcache_test gcache pthread rt)
+target_link_libraries(gcache_test gcache pthread)
 
 target_compile_options(gcache_test
   PRIVATE