This fixes a bug with the libevent backend on 32-bit platforms:

  https://github.com/wingo/fibers/issues/86

diff --git a/extensions/libevent.c b/extensions/libevent.c
index 4f44de9..52c9d73 100644
--- a/extensions/libevent.c
+++ b/extensions/libevent.c
@@ -215,7 +215,8 @@ run_event_loop (void *p)
     microsec = -1;
   else if (data->timeout >= 0)
     {
-      microsec = data->timeout / time_units_per_microsec;
+      microsec = (time_units_per_microsec == 0)
+	? 0 : data->timeout / time_units_per_microsec;
       tv.tv_sec = 0;
       tv.tv_usec = microsec;
     }
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<div class='path'>path: <a href='/guix/log/?id=7bbb329060f56ea4a102d2d7d0900fa0daf20265'>root</a>/<a href='/guix/log/etc?id=7bbb329060f56ea4a102d2d7d0900fa0daf20265'>etc</a>/<a href='/guix/log/etc/kernels-manifest.scm?id=7bbb329060f56ea4a102d2d7d0900fa0daf20265'>kernels-manifest.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/etc/kernels-manifest.scm?id=7bbb329060f56ea4a102d2d7d0900fa0daf20265&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-01-06 00:16:06 -0500'>2023-01-06</span></td><td><a href='/guix/commit/etc/kernels-manifest.scm?id=8be0a97a8139fdd4d196092008b98668f1a8b2bb'>maint: Add missing modules to the kernel manifest.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/kernels-manifest.scm: Add missing modules.
</span></span></td><td>Leo Famulari</td></tr>
<tr><td><span title='2022-12-29 13:51:58 -0500'>2022-12-29</span></td><td><a href='/guix/commit/etc/kernels-manifest.scm?id=d07d6ea31a883d395d692483d84e7797b4c2ce0f'>maint: Add a manifest for everything related to linux-libre.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/kernels-manifest.scm: New file.
* Makefile.am (EXTRA_DIST): Add it.
</span></span></td><td>Leo Famulari</td></tr>