Without <sys/time.h>, gettimeofday is undefined.

diff --git a/src/AudioIO.cpp b/src/AudioIO.cpp
index 0187e3962..e15d55f4c 100644
--- a/src/AudioIO.cpp
+++ b/src/AudioIO.cpp
@@ -479,6 +479,8 @@ time warp info and AudioIOListener and whether the playback is looped.
 #include "../lib-src/portmidi/porttime/porttime.h"
 #include "../lib-src/header-substitutes/allegro.h"
 
+#include <sys/time.h>
+
    #define MIDI_SLEEP 10 /* milliseconds */
    // how long do we think the thread that fills MIDI buffers,
    // if it is separate from the portaudio thread,
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<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
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<div class='path'>path: <a href='/guix/log/?id=b3679394ec5a703de957e4344d2e20b7e306cd39'>root</a>/<a href='/guix/log/CODE-OF-CONDUCT?id=b3679394ec5a703de957e4344d2e20b7e306cd39'>CODE-OF-CONDUCT</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/CODE-OF-CONDUCT?id=b3679394ec5a703de957e4344d2e20b7e306cd39&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2018-05-29 18:29:36 +0200'>2018-05-29</span></td><td><a href='/guix/commit/CODE-OF-CONDUCT?id=a076f19908d06b6df49f1c25c40de8838213cd71'>CODE-OF-CONDUCT: Switch to version 1.4 of the Contributor Covenant.</a><span class='msg-avail'>...<span class='msg-tooltip'>See the discussion at
&lt;https://lists.gnu.org/archive/html/guix-devel/2018-05/msg00146.html&gt;.

* CODE-OF-CONDUCT: Adapt from version 1.4 of the Contributor Covenant.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2016-04-04 23:45:57 +0200'>2016-04-04</span></td><td><a href='/guix/commit/CODE-OF-CONDUCT?id=e314ce1bd7b21229c750ab7132feac8189da87ba'>CoC: Clarify which project we're talking about.</a><span class='msg-avail'>...<span class='msg-tooltip'>* CODE-OF-CONDUCT: Define "project" and "project maintainer" as
suggested by rms.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2015-12-09 14:29:41 +0100'>2015-12-09</span></td><td><a href='/guix/commit/CODE-OF-CONDUCT?id=e15fcdd149cec662fcaf4b550ee32879bd53a591'>Add "Contributor Covenant".</a><span class='msg-avail'>...<span class='msg-tooltip'>* CODE-OF-CONDUCT: New file, adapted from
  &lt;http://contributor-covenant.org/version/1/3/0/code_of_conduct.txt&gt;.
* doc/contributing.texi (Contributing): Mention it.
* Makefile.am (EXTRA_DIST): Add it.
</span></span></td><td>Ludovic Courtès</td></tr>
/tr>
<tr><td><span title='2022-04-29 18:07:16 +0200'>2022-04-29</span></td><td><a href='/guix/commit/gnu/services/kerberos.scm?id=9d7248cd87fbda8c717341a8092780782bef0820'>services: Add missing 'description' fields.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/databases.scm (postgresql-service-type)[description]: New field.
(memcached-service-type)[description]: New field.
(mysql-service-type)[description]: New field.
(redis-service-type)[description]: New field.
* gnu/services/desktop.scm (geoclue-service-type)[description]: New
field.
(udisks-service-type)[description]: New field.
(elogind-service-type)[description]: New field.
(account-service-type)[description]: New field.
* gnu/services/kerberos.scm (krb5-service-type)[description]: New field.
(pam-krb5-service-type)[description]: New field.
* gnu/services/lirc.scm (lirc-service-type)[description]: New field.
* gnu/services/mail.scm (dovecot-service-type)[description]: New field.
(opensmtpd-service-type)[description]: New field.
(mail-aliases-service-type)[description]: New field.
(exim-service-type)[description]: New field.
* gnu/services/monitoring.scm (zabbix-server-service-type)[description]:
New field.
(zabbix-agent-service-type)[description]: New field.
* gnu/services/nfs.scm (rpcbind-service-type)[description]: New field.
(pipefs-service-type)[description]: New field.
(gss-service-type)[description]: New field.
(idmap-service-type)[description]: New field.
* gnu/services/spice.scm (spice-vdagent-service-type)[description]: New field.
* gnu/services/sysctl.scm (sysctl-service-type)[description]: New field.
* gnu/services/virtualization.scm (libvirt-service-type)[description]:
New field.
(virtlog-service-type)[description]: New field.
* gnu/services/vpn.scm (openvpn-server-service-type)[description]: New field.
(openvpn-client-service-type)[description]: New field.
(wireguard-service-type)[description]: New field.
* gnu/services/web.scm (httpd-service-type)[description]: New field.
(fcgiwrap-service-type)[description]: New field.
(agate-service-type)[description]: New field.
[name]: Fix.
</span></span></td><td>Ludovic Courtès</td></tr>