--- ./configure.ac.orig	2014-05-17 12:08:57.000000000 +0200
+++ ./configure.ac	2014-05-17 12:12:55.000000000 +0200
@@ -4,6 +4,7 @@
 AC_INIT([lcdproc], [0.5.7], [lcdproc@lists.omnipotent.net])
 AC_CONFIG_SRCDIR([clients/lcdproc/batt.c])
 AM_INIT_AUTOMAKE
+PKG_PROG_PKG_CONFIG()
 
 AC_CONFIG_HEADERS(config.h)
 
@@ -255,26 +256,62 @@
 
 dnl ######################################################################
 dnl libusb support
+dnl Stolen from the gnupg project and modified for LCDproc''s need.
+dnl
+dnl Copyright (C) 2004, 2005 Free Software Foundation, Inc.
 dnl ######################################################################
 AC_MSG_CHECKING([if libusb support has been enabled]);
-AC_ARG_ENABLE(libusb,
-	[AS_HELP_STRING([--disable-libusb],[disable USB support using libusb])],
-	[ if test "$enableval" != "no"; then
-		enable_libusb=yes
-	fi ],
-	[ enable_libusb=yes ]
-)
-AC_MSG_RESULT($enable_libusb)
+AC_ARG_WITH(libusb,
+	AC_HELP_STRING([--with-libusb=DIR],
+		[look for the libusb library in DIR]),
+		[_do_libusb=$withval],[_do_libusb=yes])
+AC_MSG_RESULT($_do_libusb)
 
-if test "$enable_libusb" = "yes"; then
-	ifdef([PKG_CHECK_MODULES],
-		[PKG_CHECK_MODULES(LIBUSB, libusb,
-			[AC_DEFINE(HAVE_LIBUSB, [1], [Define to 1 if you have libusb])],
-			[ enable_libusb=no ])],
-		[AC_MSG_WARN([pkg-config not (fully) installed; drivers requiring libusb may not be built])])
+if test "$_do_libusb" != "no" ; then
+	if test -d "$withval" ; then
+		CPPFLAGS="${CPPFLAGS} -I$withval/include"
+		LDFLAGS="${LDFLAGS} -L$withval/lib"
+		AC_PATH_PROG([_usb_config],["$_do_libusb/bin/libusb-config"])
+	else
+		AC_PATH_PROG([_usb_config],[libusb-config])
+	fi
+
+	_libusb_save_libs=$LIBS
+	_libusb_save_cflags=$CFLAGS
+
+	if test x$_usb_config != "x" ; then
+		_libusb_try_libs=`$_usb_config --libs`
+		_libusb_try_cflags=`$_usb_config --cflags`
+	else
+		_libusb_try_libs="-lusb"
+		_libusb_try_cflags=""
+	fi
+
+	LIBS="$LIBS $_libusb_try_libs"
+	CFLAGS="$CFLAGS $_libusb_try_cflags"
+
+	AC_MSG_CHECKING([whether libusb is present and sane])
+
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <usb.h>],[
+		usb_interrupt_write(NULL,0,NULL,0,0);
+		])],enable_libusb=yes,enable_libusb=no)
+
+	AC_MSG_RESULT([$enable_libusb])
+
+	if test "$enable_libusb" = "yes" ; then
+		AC_DEFINE(HAVE_LIBUSB, [1], [Define to 1 if you have libusb])
+		AC_SUBST(LIBUSB_CFLAGS, $_libusb_try_cflags)
+		AC_SUBST(LIBUSB_LIBS, $_libusb_try_libs)
+	fi
+
+	LIBS=$_libusb_save_libs
+	CFLAGS=$_libusb_save_cflags
+
+	unset _libusb_save_libs
+	unset _libusb_save_cflags
+	unset _libusb_try_libs
+	unset _libusb_try_cflags
 fi
-AC_SUBST(LIBUSB_LIBS)
-AC_SUBST(LIBUSB_CFLAGS)
 
 dnl ######################################################################
 dnl libusb-1.0 support