diff --git a/libusb/Makefile.linux b/libusb/Makefile.linux
index cf7b76c..337b556 100644
--- a/libusb/Makefile.linux
+++ b/libusb/Makefile.linux
@@ -22,7 +22,7 @@ COBJS_LIBUSB = hid.o
 COBJS = $(COBJS_LIBUSB)
 CPPOBJS   = ../hidtest/hidtest.o
 OBJS      = $(COBJS) $(CPPOBJS)
-LIBS_USB  = `pkg-config libusb-1.0 --libs` -lrt
+LIBS_USB  = `pkg-config libusb-1.0 --libs` -lrt -lpthread
 LIBS      = $(LIBS_USB)
 INCLUDES ?= -I../hidapi `pkg-config libusb-1.0 --cflags`
 
diff --git a/testgui/Makefile.linux b/testgui/Makefile.linux
index 80a54f2..d32e163 100644
--- a/testgui/Makefile.linux
+++ b/testgui/Makefile.linux
@@ -14,7 +14,7 @@ COBJS=../libusb/hid.o
 CPPOBJS=test.o
 OBJS=$(COBJS) $(CPPOBJS)
 CFLAGS=-I../hidapi -Wall -g -c `fox-config --cflags` `pkg-config libusb-1.0 --cflags`
-LIBS=-ludev -lrt `fox-config --libs` `pkg-config libusb-1.0 --libs`
+LIBS=-ludev -lrt -lpthread `fox-config --libs` `pkg-config libusb-1.0 --libs`
 
 
 testgui: $(OBJS)