Use 'uname -m', which in practice returns the processor architecture.

--- psm-3.3/buildflags.mak~	2014-08-20 21:00:18.000000000 +0100
+++ psm-3.3/buildflags.mak	2017-10-22 12:02:12.855291447 +0100
@@ -38,7 +38,7 @@
 endif
 
 export os ?= $(shell uname -s | tr '[A-Z]' '[a-z]')
-export arch := $(shell uname -p | sed -e 's,\(i[456]86\|athlon$$\),i386,')
+export arch := $(shell uname -m | sed -e 's,\(i[456]86\|athlon$$\),i386,')
 
 CC ?= gcc
 
zko.org/cgit-static/cgit.png' alt='cgit logo'/></a></td>
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<div class='path'>path: <a href='/guix/log/?id=b6b3db9f08cbe37ddbdd44a7be8a1e4824aba3d8'>root</a>/<a href='/guix/log/tests?id=b6b3db9f08cbe37ddbdd44a7be8a1e4824aba3d8'>tests</a>/<a href='/guix/log/tests/cran.scm?id=b6b3db9f08cbe37ddbdd44a7be8a1e4824aba3d8'>cran.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/cran.scm?id=b6b3db9f08cbe37ddbdd44a7be8a1e4824aba3d8&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-12-18 04:09:47 +0100'>2021-12-18</span></td><td><a href='/guix/commit/tests/cran.scm?id=10ceb3e84654e024f14a4b048e7d68492ed9dc7c'>import: cran: Fix description-&gt;package test.</a><span class='msg-avail'>...<span class='msg-tooltip'>This follows up on commit 5cd1019488c44081aaf030fbe8bc357d78daef23.

* tests/cran.scm (description): Include a very long line.
(description-&gt;package): Update the golden description to match the
paragraph filling now performed by BEAUTIFY-DESCRIPTION.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2021-07-11 00:49:16 +0200'>2021-07-11</span></td><td><a href='/guix/commit/tests/cran.scm?id=aa6921634b4ea9988af0e37bfbb56780c431ef64'>import: cran: Emit new-style package inputs.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/import/cran.scm (format-inputs): Emit symbols or
'specification-&gt;package' calls.
(maybe-inputs): Wrap in 'list' instead of 'quasiquote'.
* tests/cran.scm ("description-&gt;package"): Adjust accordingly.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-01-16 23:14:05 +0100'>2020-01-16</span></td><td><a href='/guix/commit/tests/cran.scm?id=cfd1ed84013df85f0e473884ef4038b4bd7120d4'>import: cran: Avoid uses of '@@' in the tests.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/import/cran.scm (description-&gt;alist, description-&gt;package): Export.
&lt;top level&gt;: Set! 'listify'.
* tests/cran.scm (description-alist, "description-&gt;package"): Remove use
of '@@' to access the relevant bindings.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-05-13 12:40:20 +0200'>2017-05-13</span></td><td><a href='/guix/commit/tests/cran.scm?id=db427602d8f993ee0025fa68d1af274aa8d69ab9'>import: cran: Robustify cran-package?.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/import/cran.scm (package-&gt;upstream-name): Return #f if url
  start and end index could not be determined.
  (cran-package?): Check if the upstream-name can be extracted from
  given package.
* tests/cran.scm: Add "r-minimal is not a cran package" to make sure that
  r-minimal is not detected as a cran package.

This fixes a failure of guix refresh on r-minimal because no
upsteam-name can be determined from ".../R-version.tar.gz" uri.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2017-03-08 23:42:52 +0100'>2017-03-08</span></td><td><a href='/guix/commit/tests/cran.scm?id=dd420bf3430eb644b93ca224da4c0a3f5db7a42f'>tests: Avoid zero-expression 'begin' form.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/cran.scm ("description-&gt;package"): Add body after the expected
pattern in 'match'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2016-11-10 11:58:43 +0100'>2016-11-10</span></td><td><a href='/guix/commit/tests/cran.scm?id=324a2ba56c2f4c0d91567ed08024ae2c492f3b23'>tests: Adjust 'url-fetch' mocks to TLS changes.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a followup to bc3c41ce36349ed4ec758c70b48a7059e363043a.

* tests/cpan.scm ("cpan-&gt;guix-package"): Add #:verify-certificate?
parameter in 'url-fetch' mock.
* tests/cran.scm ("description-&gt;package"): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>