unix_chkpwd is designed to have a suid bit, but it's not possible to set it
for files in the store.  This patch tells unix_pam.so to look for
unix_chkpwd in setuid program directory on Guix System.

--- a/modules/pam_unix/Makefile.in
+++ b/modules/pam_unix/Makefile.in
@@ -651,1 +651,1 @@
-	-DCHKPWD_HELPER=\"$(sbindir)/unix_chkpwd\" \
+	-DCHKPWD_HELPER=\"/run/setuid-programs/unix_chkpwd\" \
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<div class='path'>path: <a href='/guix/log/?id=d87252e633598e3cc456268e7c95ba91b2fb0d84'>root</a>/<a href='/guix/log/tests?id=d87252e633598e3cc456268e7c95ba91b2fb0d84'>tests</a>/<a href='/guix/log/tests/print.scm?id=d87252e633598e3cc456268e7c95ba91b2fb0d84'>print.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/print.scm?id=d87252e633598e3cc456268e7c95ba91b2fb0d84&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-04-20 10:57:49 +0200'>2020-04-20</span></td><td><a href='/guix/commit/tests/print.scm?id=10af34cd7f1f4f9fb50db826d06233c83a9c0439'>tests: Update expected values for package-&gt;code.</a><span class='msg-avail'>...<span class='msg-tooltip'>Reported by janneke on IRC.

* tests/print.scm: Update expected package definitions produced by package-&gt;code.
</span></span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2019-06-07 22:49:47 +0200'>2019-06-07</span></td><td><a href='/guix/commit/tests/print.scm?id=c0a4db66976dc63decbd612aafb934f44629e321'>import: print: Honor the outputs of inputs (!).</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;http://bugs.gnu.org/35893&gt;.
Reported by Jesse Gibbons &lt;jgibbons2357@gmail.com&gt;.

* guix/import/print.scm (package-&gt;code)[package-lists-&gt;code]: Preserve
OUT in the result.
* tests/print.scm (define-with-source): New macro.
(pkg): Use it.
(pkg-source): New variable.
(pkg-with-inputs, pkg-with-inputs-source): New variables.
("simple package"): Refer to 'pkg-source'.
("package with inputs"): New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-09-28 13:10:10 +0200'>2017-09-28</span></td><td><a href='/guix/commit/tests/print.scm?id=68a91a183b29c62232fb048bb27e10b6ff2e39dd'>import: Add package-&gt;code.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/import/print.scm: New file.
* tests/print.scm: New file.
* Makefile.am (SCM_TESTS): Add new test file.
(MODULES): Add print.scm.
</span></span></td><td>Ricardo Wurmus</td></tr>