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
4271'>refs</a><a class='active' href='/guix/log/gnu/tests/messaging.scm'>log</a><a href='/guix/tree/gnu/tests/messaging.scm?id=82c791a3b153dc01cc44521f14564c8a9df74271'>tree</a><a href='/guix/commit/gnu/tests/messaging.scm?id=82c791a3b153dc01cc44521f14564c8a9df74271'>commit</a><a href='/guix/diff/gnu/tests/messaging.scm?id=82c791a3b153dc01cc44521f14564c8a9df74271'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/tests/messaging.scm'>
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<div class='path'>path: <a href='/guix/log/?id=82c791a3b153dc01cc44521f14564c8a9df74271'>root</a>/<a href='/guix/log/gnu?id=82c791a3b153dc01cc44521f14564c8a9df74271'>gnu</a>/<a href='/guix/log/gnu/tests?id=82c791a3b153dc01cc44521f14564c8a9df74271'>tests</a>/<a href='/guix/log/gnu/tests/messaging.scm?id=82c791a3b153dc01cc44521f14564c8a9df74271'>messaging.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/tests/messaging.scm?id=82c791a3b153dc01cc44521f14564c8a9df74271&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2018-12-24 11:18:36 +0200'>2018-12-24</span></td><td><a href='/guix/commit/gnu/tests/messaging.scm?id=dcad57d5fca43a111e1b314264171c80d4d9a75b'>services: Add quassel.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/messaging.scm (&lt;quassel-configuration&gt;): New record type.
(%quassel-account, %quassel-activation): New procedures.
(quassel-service-type): New variable.
* gnu/tests/messaging.scm (%test-quassel): New variable.
(run-quassel-test): New procedure.
* doc/guix.texi (Messaging): Document quassel service.
</span></span></td><td>Efraim Flashner</td></tr>