Copied from Debian.

From: Jérémy Bobbio <lunar@debian.org>
Subject: Remove build date
Bug-Debian: http://bugs.debian.org/782851
 In order to make unzip build reproducibly, we remove the
 (already optional) build date from the binary.

--- a/unix/unix.c
+++ b/unix/unix.c
@@ -1705,7 +1705,7 @@
 #endif /* Sun */
 #endif /* SGI */
 
-#ifdef __DATE__
+#if 0
       " on ", __DATE__
 #else
       "", ""
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<div class='path'>path: <a href='/guix/log/?id=ed8e60f24a02e31fac653da3d714c7a2d880bf8a'>root</a>/<a href='/guix/log/tests?id=ed8e60f24a02e31fac653da3d714c7a2d880bf8a'>tests</a>/<a href='/guix/log/tests/openpgp.scm?id=ed8e60f24a02e31fac653da3d714c7a2d880bf8a'>openpgp.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/tests/openpgp.scm?id=ed8e60f24a02e31fac653da3d714c7a2d880bf8a&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-12-22 10:53:19 +0100'>2021-12-22</span></td><td><a href='/guix/commit/tests/openpgp.scm?id=9ebc9ca070a21ba0aeb3f61202a8071bb250ccc8'>tests: Move keys into ./tests/keys/ and add a third ed25519 key.</a><span class='msg-avail'>...</span></td><td>Attila Lendvai</td></tr>
1-29 12:09:52 +0100'>2019-01-29</span></td><td><a href='/guix/commit/tests/status.scm?id=73a8681a16869a2b3a9da1c7ba9434e07a204e19'>status: Keep track of build completion as reported by build tools.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-01-29 12:09:52 +0100'>2019-01-29</span></td><td><a href='/guix/commit/tests/status.scm?id=976ef2d97887d16eab8d4eb9dad811786b04d690'>status: Record more information about builds.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-01-09 14:47:53 +0100'>2019-01-09</span></td><td><a href='/guix/commit/tests/status.scm?id=a65177a657b0cb36d45f2e8db574ea9c10f89a1f'>maint: Remove 'cond-expand' forms for Guile 2.0.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-10-16 17:12:09 -0500'>2018-10-16</span></td><td><a href='/guix/commit/tests/status.scm?id=278f86a43f1561b1c064ce88da012db414ec7efc'>ui: Fix port-buffering with guile@2.0.</a><span class='msg-avail'>...</span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2018-10-15 23:06:55 +0200'>2018-10-15</span></td><td><a href='/guix/commit/tests/status.scm?id=f9a8fce10f2d99efec7cb1dd0f6c5f0df9d1b2df'>status: Build upon multiplexed build output.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-10-09 18:54:12 +0200'>2018-10-09</span></td><td><a href='/guix/commit/tests/status.scm?id=fe17037b387c6eca0c45f0526d2761e982a192bb'>status: Gracefully handle invalid UTF-8 in build logs.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>