Index: link-grammar/Makefile.am
--- link-grammar/Makefile.am.orig
+++ link-grammar/Makefile.am
@@ -81,6 +81,9 @@ liblink_grammar_la_LIBADD  += ${PTHREAD_LIBS}
 # It seems no mathematical function is used now. Keep it to be on the safe side.
 liblink_grammar_la_LIBADD  += -lm
 
+# for call_once
+liblink_grammar_la_LIBADD  += -lstdthreads
+
 if WITH_CXXREGEX
 dict-common/regex-morph.lo: AM_CFLAGS = -x c++ $(CXXFLAGS) $(WARN_CXXFLAGS)
 dict-common/regex-morph.lo: CFLAGS =
