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):
pts</option>
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<div class='path'>path: <a href='/guix/log/?id=744e8f7d046a07e4559b1e66bcb4683a197873ff&amp;showmsg=1'>root</a>/<a href='/guix/log/bootstrap?id=744e8f7d046a07e4559b1e66bcb4683a197873ff&amp;showmsg=1'>bootstrap</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/bootstrap?id=744e8f7d046a07e4559b1e66bcb4683a197873ff'>Collapse</a>)</th><th class='left'>Author</th></tr>
<tr class='logheader'><td><span title='2024-04-19 16:45:41 +0200'>2024-04-19</span></td><td class='logsubject'><a href='/guix/commit/bootstrap?id=2b8a2a6e723a0cf987c814865df9368e6348b6f8'>maint: Generate doc/version[-LANG].texi using `mdate-from-git.scm'.</a></td><td>Janneke Nieuwenhuizen</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
This replaces Automake's `build-aux/mdate-sh' with our own
`build-aux/mdate-from-git.scm' to use reproducible timestamps from Git
instead.

* build-aux/mdate-from-git.scm: New script.
* bootstrap: Use it to replace build-aux/mdate-sh.
* Makefile.am (EXTRA_DIST): Add it.

Change-Id: I17d0a7de9ffea397129c0db1728f86e28a4e245f


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<tr class='logheader'><td><span title='2021-06-13 20:46:01 +0200'>2021-06-13</span></td><td class='logsubject'><a href='/guix/commit/bootstrap?id=bd02e50a02ceed914135dba1e69e4457e489cf86'>bootstrap: Simplify search for translation languages.</a></td><td>Hartmut Goebel</td></tr>
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Extend the sed script to also behave like "basename",
saving the addtional call of "xargs basename".

* bootstrap (langs): Extend sed scripts, remove running xargs.


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