added mathlibs back to check dig

plugins/Makefile.am

@@ -69,7 +69,7 @@ test-debug:
 check_apt_LDADD = $(BASEOBJS)
 check_cluster_LDADD = $(BASEOBJS)
 check_dbi_LDADD = $(NETLIBS) $(DBILIBS)
-check_dig_LDADD = $(NETLIBS)
+check_dig_LDADD = $(NETLIBS) $(MATHLIBS)
 check_disk_LDADD = $(BASEOBJS)
 check_dns_LDADD = $(NETLIBS)
 check_dummy_LDADD = $(BASEOBJS)