--- configure.ac
+++ configure.ac
@@ -197,7 +197,8 @@ dnl We are using our own libltdl checks
 dnl because we do not want to ship our own copy of libltdl any more.
 dnl Not shipping libltdl makes it possible to ditch our own autogen.sh
 dnl and relying on standard autoconf's "autoreconf".
-GP_LIB_LTDL
+dnl GP_LIB_LTDL
+AC_WITH_LTDL
 
 
 # report on compiler/libtool setup
--- libgphoto2_port/configure.ac
+++ libgphoto2_port/configure.ac
@@ -78,7 +78,8 @@ dnl We are using our own libltdl checks
 dnl because we do not want to ship our own copy of libltdl any more.
 dnl Not shipping libltdl makes it possible to ditch our own autogen.sh
 dnl and relying on standard autoconf's "autoreconf".
-GP_LIB_LTDL
+dnl GP_LIB_LTDL
+AC_WITH_LTDL
 
 
 # report on compiler/libtool setup
@@ -337,7 +338,7 @@ dnl libusb
 dnl ---------------------------------------------------------------------------
 GP_CONFIG_MSG([USB ports])
 GP_CHECK_LIBRARY([LIBUSB],[libusb],[>= 0.1.5],
-		[usb.h],[usb_busses],[
+		[usb.h],[usb_open],[
 	IOLIB_SUBDIRS="$IOLIB_SUBDIRS usb"
 ],[],
 		[disable-explicitly],