Use 'pkg-config' instead of heuristics to find 'tk' flags.

--- matplotlib-1.4.3/setupext.py.orig	2015-12-01 14:21:19.554417453 +0100
+++ matplotlib-1.4.3/setupext.py	2015-12-02 10:39:47.282363530 +0100
@@ -1457,7 +1457,7 @@
             p = subprocess.Popen(
                 '. %s ; eval echo ${%s}' % (file, varname),
                 shell=True,
-                executable="/bin/sh",
+                executable="sh",
                 stdout=subprocess.PIPE)
             result = p.communicate()[0]
             return result.decode('ascii')
@@ -1601,8 +1601,19 @@
             #      of distros.
 
             # Query Tcl/Tk system for library paths and version string
+            def getoutput(s):
+                ret = os.popen(s).read().strip()
+                return ret
             try:
-                tcl_lib_dir, tk_lib_dir, tk_ver = self.query_tcltk()
+                pkg_config_libs = getoutput('pkg-config --libs-only-L tk').split()
+                # drop '-L' part of strings
+                pkg_config_libs = [s[2:] for s in pkg_config_libs]
+                pkg_config_ver = getoutput('pkg-config --modversion tk')
+                tk_ver = re.match(r"(\d+.\d+)[\d.]*", pkg_config_ver).group(1)
+                tcl_lib_dir = next(s for s in pkg_config_libs
+                                   if re.match(r".*-tcl-.*", s)) + '/tcl' + tk_ver
+                tk_lib_dir = next(s for s in pkg_config_libs
+                                  if re.match(r".*-tk-.*", s)) + '/tk' + tk_ver
             except:
                 tk_ver = ''
                 result = self.hardcoded_tcl_config()
c4531608e0'/><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=031f705a438e25af3b0fd1fe1b6453c4531608e0'>root</a>/<a href='/guix/log/tests?id=031f705a438e25af3b0fd1fe1b6453c4531608e0'>tests</a>/<a href='/guix/log/tests/cve.scm?id=031f705a438e25af3b0fd1fe1b6453c4531608e0'>cve.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/cve.scm?id=031f705a438e25af3b0fd1fe1b6453c4531608e0&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-10-23 16:40:17 +0200'>2019-10-23</span></td><td><a href='/guix/commit/tests/cve.scm?id=74afaa37d5dec1a9d1b83951529ba69d8947fb07'>cve: Rewrite to read the JSON feed instead of the XML feed.</a><span class='msg-avail'>...<span class='msg-tooltip'>The XML feed was discontinued on Oct. 16th, 2019:

  &lt;https://nvd.nist.gov/General/News/XML-Vulnerability-Feed-Retirement-Phase-3&gt;

* guix/cve.scm (string-&gt;date*): New procedure.
(&lt;cve-item&gt;, &lt;cve&gt;, &lt;cve-reference&gt;): New record types.
(cpe-match-&gt;cve-configuration, configuration-data-&gt;cve-configurations)
(json-&gt;cve-items, version-matches?): New procedures.
(yearly-feed-uri): Change URL to refer to JSON feed.
(cpe-&gt;product-alist, %parse-vulnerability-feed)
(xml-&gt;vulnerabilities): Remove.
(cve-configuration-&gt;package-list, merge-package-lists)
(cve-item-&gt;vulnerability, json-&gt;vulnerabilities): New procedures.
(write-cache): Use 'json-&gt;vulnerabilities' instead of
'xml-&gt;vulnerabilities', and remove 'parameterize'.
(vulnerabilities-&gt;lookup-proc): Use 'version-matches?' when VERSION is
true.
* tests/cve.scm (%sample): Use 'tests/cve-sample.json'.
(%expected-vulnerabilities): Rewrite accordingly.
("json-&gt;cve-items", "cve-item-published-date")
("json-&gt;vulnerabilities"): New tests.
("xml-&gt;vulnerabilities"): Remove.
("vulnerabilities-&gt;lookup-proc"): Adjust to new vulnerabilities.
* tests/cve-sample.json: New file.
* tests/cve-sample.xml: Remove.
* Makefile.am (EXTRA_DIST): Adjust accordingly.
* doc/guix.texi (Invoking guix lint): Update nist.gov URLs.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-10-20 23:26:50 +0200'>2019-10-20</span></td><td><a href='/guix/commit/tests/cve.scm?id=79c03e55e26d88c8d327daced02367abe7f17f91'>tests: Avoid now-deprecated 'make-struct'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/cve.scm (vulnerability): Use 'make-struct/no-tail' instead of
'make-struct', which is deprecated.
* tests/lint.scm ("cve: one vulnerability")
("cve: one patched vulnerability")
("cve: known safe from vulnerability")
("cve: vulnerability fixed in replacement version")
("cve: patched vulnerability in replacement"): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>