diff --git a/smmapdfw/configure.ac b/smmapdfw/configure.ac
index 5e84cbe..71cdf79 100644
--- a/smmapdfw/configure.ac
+++ b/smmapdfw/configure.ac
@@ -16,7 +16,8 @@ AC_CHECK_LIB(pthread, pthread_create,
              [ CFLAGS="$CFLAGS -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS"
                LIBS="$LIBS -lpthread"],
              AC_CHECK_LIB(c_r, pthread_create, 
-                          [ CFLAGS="$CFLAGS -pthread -D_THREAD_SAFE" ],
+                          [ CFLAGS="$CFLAGS -pthread -D_THREAD_SAFE" 
+                            LIBS="$LIBS -lc_r"],
                           [AC_MSG_ERROR([*** we can't go without threads])]
              )
 )