diff --git a/urjtag/ChangeLog b/urjtag/ChangeLog
index ce732d7b..03e27371 100644
--- a/urjtag/ChangeLog
+++ b/urjtag/ChangeLog
@@ -12,6 +12,8 @@
   * data/analog/bf518/bf518, data/analog/bf548/bf548: Rename a few bus
     signals to use the same style as all other buses.
 
+  * configure.ac (HAVE_LIBUSB1): Only define when we detect libusb-1.0.pc.
+
 2010-10-26  Mike Frysinger  <vapier@gentoo.org>
 
   * src/tap/cable_list.h, src/tap/cable/generic_usbconn_list.h,
diff --git a/urjtag/configure.ac b/urjtag/configure.ac
index ed3a35a9..8e9ee407 100644
--- a/urjtag/configure.ac
+++ b/urjtag/configure.ac
@@ -183,8 +183,10 @@ AS_IF([test "x$with_libusb" != xno], [
     LIBUSB_CFLAGS="-I$with_libusb -I$with_libusb/include"
   ], [
     AS_IF([test "x$with_libusb" != x0.1 -a "x$HAVELIBUSB" = xno], [
-      PKG_CHECK_MODULES(LIBUSB, libusb-1.0, [HAVELIBUSB=1.0], [:])
-      AC_DEFINE(HAVE_LIBUSB1, 1, [Define if you have libusb-1.0])
+      PKG_CHECK_MODULES(LIBUSB, libusb-1.0, [
+          HAVELIBUSB=1.0
+          AC_DEFINE(HAVE_LIBUSB1, 1, [Define if you have libusb-1.0])
+        ], [:])
     ])
     AS_IF([test "x$with_libusb" != x1.0 -a "x$HAVELIBUSB" = xno], [
       PKG_CHECK_MODULES(LIBUSB, libusb, [HAVELIBUSB=0.1], [:])