Dfu-programmer cannot cannot find libusb. This patch fixes that.

diff --git a/src/dfu-device.h b/src/dfu-device.h
index bbdfa99..31af0e8 100644
--- a/src/dfu-device.h
+++ b/src/dfu-device.h
@@ -6,7 +6,7 @@
 #endif
 #include <stdint.h>
 #ifdef HAVE_LIBUSB_1_0
-#include <libusb.h>
+#include <libusb-1.0/libusb.h>
 #else
 #include <usb.h>
 #endif

diff --git a/src/main.c b/src/main.c
index ef2aa16..dcc3636 100644
--- a/src/main.c
+++ b/src/main.c
@@ -24,7 +24,7 @@
 #include <stdio.h>
 #include <string.h>
 #ifdef HAVE_LIBUSB_1_0
-#include <libusb.h>
+#include <libusb-1.0/libusb.h>
 #else
 #include <usb.h>
 #endif

diff --git a/src/dfu.c b/src/dfu.c
index 7dbcc57..952e896 100644
--- a/src/dfu.c
+++ b/src/dfu.c
@@ -27,7 +27,7 @@
 #include <stdlib.h>
 #include <stddef.h>
 #ifdef HAVE_LIBUSB_1_0
-#include <libusb.h>
+#include <libusb-1.0/libusb.h>
 #else
 #include <usb.h>
 #endif

diff --git a/src/dfu.h b/src/dfu.h
index 2a159e8..63510f2 100644
--- a/src/dfu.h
+++ b/src/dfu.h
@@ -25,7 +25,7 @@
 # include <config.h>
 #endif
 #ifdef HAVE_LIBUSB_1_0
-#include <libusb.h>
+#include <libusb-1.0/libusb.h>
 #else
 #include <usb.h>
 #endif
refs</a><a class='active' href='/guix/log/gnu/services/vpn.scm'>log</a><a href='/guix/tree/gnu/services/vpn.scm?id=ad9e007e620d4274ac9e41b806bab86c66dfd734'>tree</a><a href='/guix/commit/gnu/services/vpn.scm?id=ad9e007e620d4274ac9e41b806bab86c66dfd734'>commit</a><a href='/guix/diff/gnu/services/vpn.scm?id=ad9e007e620d4274ac9e41b806bab86c66dfd734'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/services/vpn.scm'>
<input type='hidden' name='id' value='ad9e007e620d4274ac9e41b806bab86c66dfd734'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=ad9e007e620d4274ac9e41b806bab86c66dfd734'>root</a>/<a href='/guix/log/gnu?id=ad9e007e620d4274ac9e41b806bab86c66dfd734'>gnu</a>/<a href='/guix/log/gnu/services?id=ad9e007e620d4274ac9e41b806bab86c66dfd734'>services</a>/<a href='/guix/log/gnu/services/vpn.scm?id=ad9e007e620d4274ac9e41b806bab86c66dfd734'>vpn.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/services/vpn.scm?id=ad9e007e620d4274ac9e41b806bab86c66dfd734&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2017-10-10 22:06:08 +0200'>2017-10-10</span></td><td><a href='/guix/commit/gnu/services/vpn.scm?id=4b8b4418e609b5e0bfb6efbc11ac28deaa437e80'>services: vpn: Fix default tls-auth configuration.</a><span class='msg-avail'>...</span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2017-03-31 20:55:05 -0500'>2017-03-31</span></td><td><a href='/guix/commit/gnu/services/vpn.scm?id=9fc221b58cecd73e22cac01cb0918a774a4a7b2f'>doc: Fix typos.</a><span class='msg-avail'>...</span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2017-03-24 16:09:18 +0100'>2017-03-24</span></td><td><a href='/guix/commit/gnu/services/vpn.scm?id=85ac401acf2e33e4cb6d1510ac24867dc516e656'>services: openvpn: Fix a typo which was corrected in generated doc.</a><span class='msg-avail'>...</span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2017-01-25 14:05:37 +0100'>2017-01-25</span></td><td><a href='/guix/commit/gnu/services/vpn.scm?id=e57bd0bed86caac304e5f37c5653e6b13858c7c5'>services: Fix 'mkdir-p' in activation scripts.</a><span class='msg-avail'>...</span></td><td>Clément Lassieur</td></tr>
<tr><td><span title='2017-01-20 21:39:17 +0100'>2017-01-20</span></td><td><a href='/guix/commit/gnu/services/vpn.scm?id=be051880c435d19e7788d5df56c062f7797e0a49'>services: Reindent vpn.scm.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-01-15 12:24:52 +0100'>2017-01-15</span></td><td><a href='/guix/commit/gnu/services/vpn.scm?id=2be1b4712d362fa9face12a731e75038ae9d59ba'>gnu: Add openvpn service.</a><span class='msg-avail'>...</span></td><td>Julien Lepiller</td></tr>