Index: head/biology/iolib/Makefile
===================================================================
--- head/biology/iolib/Makefile	(revision 497507)
+++ head/biology/iolib/Makefile	(revision 497508)
@@ -1,25 +1,26 @@
 # Created by: Wen Heping <wenheping@gmail.com>
 # $FreeBSD$
 
 PORTNAME=	io_lib
 DISTVERSIONPREFIX=	${PORTNAME}-
 DISTVERSION=	1-14-10
 CATEGORIES=	biology
 
 MAINTAINER=	danilo@FreeBSD.org
 COMMENT=	General purpose trace file (and Experiment File) reading interface
 
 LICENSE=	BSD3CLAUSE
 
 LIB_DEPENDS=	libcurl.so:ftp/curl
 
 USES=		autoreconf gmake libtool
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	jkbonfield
 
 GNU_CONFIGURE=	yes
 USE_LDCONFIG=	yes
 INSTALL_TARGET=	install-strip
+LDFLAGS+=	-lpthread
 
 .include <bsd.port.mk>