add additional checking for checking compiler support of -pthread.

configure.in

@@ -750,7 +750,7 @@ then
 	echo 'int main() { return 0; }' | cat > conftest.c
 	${CC-cc} -pthread -o conftest conftest.c > conftest.out 2>&1
 	if test $? -eq 0; then
-		if test -z "`egrep -i '(unrecognize|unknown)' conftest.out | grep pthread`"; then
+		if test -z "`egrep -i '(unrecognize|unknown)' conftest.out | grep pthread`" && test -z "`egrep -i '(error|incorrect)' conftest.out`" ; then
 			ac_cv_have_dash_pthread=yes
 			CFLAGS="$CFLAGS -pthread"
 			CXXFLAGS="$CXXFLAGS -pthread"