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
href='/guix/log/HACKING'>log</a><a href='/guix/tree/HACKING?id=e64eae64e1500aefbda3471612603792c5b4e07f'>tree</a><a href='/guix/commit/HACKING?id=e64eae64e1500aefbda3471612603792c5b4e07f'>commit</a><a href='/guix/diff/HACKING?id=e64eae64e1500aefbda3471612603792c5b4e07f'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/HACKING'>
<input type='hidden' name='id' value='e64eae64e1500aefbda3471612603792c5b4e07f'/><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=e64eae64e1500aefbda3471612603792c5b4e07f'>root</a>/<a href='/guix/log/HACKING?id=e64eae64e1500aefbda3471612603792c5b4e07f'>HACKING</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/HACKING?id=e64eae64e1500aefbda3471612603792c5b4e07f&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-10-23 12:57:20 -0400'>2020-10-23</span></td><td><a href='/guix/commit/HACKING?id=73faee9fb25465f1b236f5f94e1052145655736f'>doc: Fix typo in HACKING.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Contributing): s/informations/information/.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2020-01-09 23:33:04 +0100'>2020-01-09</span></td><td><a href='/guix/commit/HACKING?id=2d315cd428484537e763d7f7c676dc5fff7995f6'>doc: Move "Commit Access" section from 'HACKING' to the manual.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Remove.
(Contributing): Update URL of the manual.
* doc/contributing.texi (Commit Access): New section.
(Submitting Patches): Add cross reference.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-01-09 23:33:04 +0100'>2020-01-09</span></td><td><a href='/guix/commit/HACKING?id=a7bde77d247ed0765f5378779d67b4668c5d7648'>doc: Add "Tracking Bugs and Patches" section.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/contributing.texi (Tracking Bugs and Patches): New section.
(Submitting Patches): Refer to it.
* doc/guix.texi: Update copyright line.
* HACKING (Using emacs-debbugs): Remove.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-07-13 14:25:19 -0400'>2019-07-13</span></td><td><a href='/guix/commit/HACKING?id=06e1ecbf17fee7fe513ad2808d8175fb3565ae3e'>doc: Update keyserver URL.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Change keyserver URL to 'keys.openpgp.org'.
</span></span></td><td>Leo Famulari</td></tr>
<tr><td><span title='2019-02-11 23:23:27 +0100'>2019-02-11</span></td><td><a href='/guix/commit/HACKING?id=6701edbfad62ba9572ffd35497df3db27b208ba5'>HACKING: Update key server.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Recommend pool.sks-keyservers.net.
</span></span></td><td>Ludovic Courtès</td></tr>