Fix check for dmenu (open file mode, dependency on which).

See <https://github.com/proxypoke/quickswitch-for-i3/pull/24>.

--- quickswitch-i3-2.2/quickswitch.py	2016-09-18 19:59:10.257765542 +0200
+++ quickswitch-i3-2.2/quickswitch.py	2016-09-21 10:43:01.277577819 +0200
@@ -24,9 +24,10 @@
 
 import argparse
 import subprocess
-import os
 import re
 
+from distutils.spawn import find_executable
+
 try:
     import i3
 except ImportError:
@@ -37,11 +38,8 @@
 
 def check_dmenu():
     '''Check if dmenu is available.'''
-    devnull = open(os.devnull)
-    retcode = subprocess.call(["which", "dmenu"],
-                              stdout=devnull,
-                              stderr=devnull)
-    return True if retcode == 0 else False
+    executable = find_executable("dmenu")
+    return executable != None
 
 
 def dmenu(options, dmenu):
cripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=d7942ac12ad51615cd43d3debb8b561a503e8fc0'>refs</a><a class='active' href='/guix/log/gnu/packages/patches/unzip-alt-iconv-utf8.patch'>log</a><a href='/guix/tree/gnu/packages/patches/unzip-alt-iconv-utf8.patch?id=d7942ac12ad51615cd43d3debb8b561a503e8fc0'>tree</a><a href='/guix/commit/gnu/packages/patches/unzip-alt-iconv-utf8.patch?id=d7942ac12ad51615cd43d3debb8b561a503e8fc0'>commit</a><a href='/guix/diff/gnu/packages/patches/unzip-alt-iconv-utf8.patch?id=d7942ac12ad51615cd43d3debb8b561a503e8fc0'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/patches/unzip-alt-iconv-utf8.patch'>
<input type='hidden' name='id' value='d7942ac12ad51615cd43d3debb8b561a503e8fc0'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=d7942ac12ad51615cd43d3debb8b561a503e8fc0'>root</a>/<a href='/guix/log/gnu?id=d7942ac12ad51615cd43d3debb8b561a503e8fc0'>gnu</a>/<a href='/guix/log/gnu/packages?id=d7942ac12ad51615cd43d3debb8b561a503e8fc0'>packages</a>/<a href='/guix/log/gnu/packages/patches?id=d7942ac12ad51615cd43d3debb8b561a503e8fc0'>patches</a>/<a href='/guix/log/gnu/packages/patches/unzip-alt-iconv-utf8.patch?id=d7942ac12ad51615cd43d3debb8b561a503e8fc0'>unzip-alt-iconv-utf8.patch</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/gnu/packages/patches/unzip-alt-iconv-utf8.patch?id=d7942ac12ad51615cd43d3debb8b561a503e8fc0&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-03-14 06:11:20 +0100'>2021-03-14</span></td><td><a href='/guix/commit/gnu/packages/patches/unzip-alt-iconv-utf8.patch?id=31d289a4759909d24dd309ac24d42902a8c20da0'>gnu: unzip: Add patches from Fedora [security fixes].</a><span class='msg-avail'>...<span class='msg-tooltip'>Non-exhaustively fixes CVE-2016-9844, CVE-2018-1000035, CVE-2018-18384, and
CVE-2019-13232.

* gnu/packages/patches/unzip-COVSCAN-fix-unterminated-string.patch,
gnu/packages/patches/unzip-CVE-2016-9844.patch,
gnu/packages/patches/unzip-CVE-2018-1000035.patch,
gnu/packages/patches/unzip-CVE-2018-18384.patch,
gnu/packages/patches/unzip-case-insensitive.patch,
gnu/packages/patches/unzip-alt-iconv-utf8-print.patch,
gnu/packages/patches/unzip-alt-iconv-utf8.patch,
gnu/packages/patches/unzip-close.patch,
gnu/packages/patches/unzip-exec-shield.patch,
gnu/packages/patches/unzip-fix-recmatch.patch,
gnu/packages/patches/unzip-manpage-fix.patch,
gnu/packages/patches/unzip-overflow.patch,
gnu/packages/patches/unzip-symlink.patch,
gnu/packages/patches/unzip-timestamp.patch,
gnu/packages/patches/unzip-valgrind.patch,
gnu/packages/patches/unzip-x-option.patch,
gnu/packages/patches/unzip-zipbomb-manpage.patch,
gnu/packages/patches/unzip-zipbomb-part1.patch,
gnu/packages/patches/unzip-zipbomb-part2.patch,
gnu/packages/patches/unzip-zipbomb-part3.patch: New patches.
* gnu/local.mk (dist_patch_DATA): Register them.
* gnu/packages/compression.scm (unzip/fixed): New variable. Apply patches.
(unzip)[replacement]: Graft.
</span></span></td><td>Léo Le Bouter</td></tr>