diff -up gnuradio-3.4.0/config/usrp_libusb.m4.orig gnuradio-3.4.0/config/usrp_libusb.m4
--- gnuradio-3.4.0/config/usrp_libusb.m4.orig	2011-06-12 05:54:36.000000000 +0200
+++ gnuradio-3.4.0/config/usrp_libusb.m4	2011-06-28 11:34:32.893634688 +0200
@@ -160,36 +160,6 @@ AC_DEFUN([USRP_LIBUSB], [
         AC_MSG_RESULT([$libusbok])
         LIBS="$save_LIBS"
         AC_LANG_POP(C)
-
-        if test $libusbok = yes; then
-          if test ${libusb_name} != "libusb-1.0"; then
-            dnl PKGCONFIG found a legacy version of libusb; make sure the
-            dnl variable _usb_debug is available in the found library.
-	    dnl Do not test on Windows, since that symbol is not defined.
-            case "$host_os" in
-              cygwin* | mingw*)
-              ;;
-            *)
-              AC_LANG_PUSH(C)
-              save_CPPFLAGS="$CPPFLAGS"
-              if test x$USB_INCLUDEDIR != x; then
-                CPPFLAGS="$USB_INCLUDES"
-              fi
-              save_LIBS="$LIBS"
-              LIBS="$USB_LIBS"
-              AC_MSG_CHECKING([$libusb_name for symbol usb_debug in library $usb_lib_name])
-              AC_LINK_IFELSE([AC_LANG_PROGRAM([[
-                extern int usb_debug;]],
-                [[usb_debug = 0;]])],
-                [libusbok=yes],[libusbok=no])
-              AC_MSG_RESULT([$libusbok])
-              LIBS="$save_LIBS"
-              CPPFLAGS="$save_CPPFLAGS"
-              AC_LANG_POP(C)
-              ;;
-            esac
-          fi
-        fi
       fi
     fi
     dnl if everything checks out OK, finish up