diff --git a/libs/pbd/wscript b/libs/pbd/wscript
index b050544524..354d757be0 100644
--- a/libs/pbd/wscript
+++ b/libs/pbd/wscript
@@ -142,6 +142,7 @@ def build(bld):
         testobj.includes     = obj.includes + ['test', '../pbd']
         testobj.uselib       = 'CPPUNIT XML SNDFILE'
         testobj.use          = 'libpbd'
+        testobj.linkflags    = ['-lrt']
 
 
 def shutdown():