diff --git a/tools/bif-coverage/project.xml b/tools/bif-coverage/project.xml
index fa94320..9f0c97d 100644
--- a/tools/bif-coverage/project.xml
+++ b/tools/bif-coverage/project.xml
@@ -11,6 +11,8 @@
     <unitPaths>
       <path>src/main/pascal</path>
       <path>../../compiler/src/main/pascal</path>
+      <!-- SysUtils and other stdlib units the analyser uses. -->
+      <path>../../stdlib/src/main/pascal</path>
     </unitPaths>
   </build>
 </project>