diff --git a/urjtag/configure.ac b/urjtag/configure.ac
index a1a58e39..26e627f4 100644
--- a/urjtag/configure.ac
+++ b/urjtag/configure.ac
@@ -182,6 +182,7 @@ AS_IF([test "x$with_libusb" != xno], [
   ], [
     AS_IF([test "x$with_libusb" != x0.1 -a "x$HAVELIBUSB" = xno], [
       PKG_CHECK_MODULES(LIBUSB, libusb-1.0, [HAVELIBUSB=1.0], [:])
+      AC_DEFINE(HAVE_LIBUSB1, 1, [Define if you have libusb-1.0])
     ])
     AS_IF([test "x$with_libusb" != x1.0 -a "x$HAVELIBUSB" = xno], [
       PKG_CHECK_MODULES(LIBUSB, libusb, [HAVELIBUSB=0.1], [:])
@@ -196,6 +197,8 @@ AS_IF([test "x$with_libusb" != xno], [
       AC_DEFINE(HAVE_LIBUSB, 1, [Define if you have libusb])
     ])
   ])
+  AS_VAR_APPEND([LIBS], " $LIBUSB_LIBS")
+  AS_VAR_APPEND([CPPFLAGS], " $LIBUSB_CFLAGS")
 ])
 AM_CONDITIONAL(HAVE_LIBUSB, [test "x$HAVELIBUSB" != "xno"])