diff -ruN polyml-5.8.2.orig/configure.ac polyml-5.8.2/configure.ac
--- polyml-5.8.2.orig/configure.ac	2021-05-02 13:53:42.000000000 +0200
+++ polyml-5.8.2/configure.ac	2021-09-10 19:29:27.370699622 +0200
@@ -198,7 +198,7 @@
     # Solaris needs -lsocket, -lnsl and -lrt
     AC_SEARCH_LIBS([gethostbyname], [nsl])
     AC_SEARCH_LIBS([getsockopt], [socket])
-    AC_SEARCH_LIBS([sem_wait], [rt])
+    AC_SEARCH_LIBS([sem_wait], [rt] [pthread])
 
     # Check for X and Motif headers and libraries
     AC_PATH_X