Adopted from NixOS
pkgs/development/libraries/kde-frameworks/kio/samba-search-path.patch

===================================================================
--- kio-5.17.0.orig/src/core/ksambashare.cpp
+++ kio-5.17.0/src/core/ksambashare.cpp
@@ -67,13 +67,18 @@ KSambaSharePrivate::~KSambaSharePrivate(
 
 bool KSambaSharePrivate::isSambaInstalled()
 {
-    if (QFile::exists(QStringLiteral("/usr/sbin/smbd"))
-            || QFile::exists(QStringLiteral("/usr/local/sbin/smbd"))) {
-        return true;
+    const QByteArray pathEnv = qgetenv("PATH");
+    if (!pathEnv.isEmpty()) {
+        QLatin1Char pathSep(':');
+        QStringList paths = QFile::decodeName(pathEnv).split(pathSep, QString::SkipEmptyParts);
+        for (QStringList::iterator it = paths.begin(); it != paths.end(); ++it) {
+            it->append(QStringLiteral("/smbd"));
+            if (QFile::exists(*it)) {
+                return true;
+            }
+        }
     }
 
-    //qDebug() << "Samba is not installed!";
-
     return false;
 }
 
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<div class='path'>path: <a href='/guix/log/?id=6c5d358cc25ca94d9c0c75a3a086e81b2d63d1b6'>root</a>/<a href='/guix/log/tests?id=6c5d358cc25ca94d9c0c75a3a086e81b2d63d1b6'>tests</a>/<a href='/guix/log/tests/cpan.scm?id=6c5d358cc25ca94d9c0c75a3a086e81b2d63d1b6'>cpan.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/cpan.scm?id=6c5d358cc25ca94d9c0c75a3a086e81b2d63d1b6&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-01-15 18:40:43 +0100'>2020-01-15</span></td><td><a href='/guix/commit/tests/cpan.scm?id=4aea90b1876179aab8d603a42533a6bdf97ccd3c'>import: cpan: Rewrite tests to use an HTTP server instead of mocking.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/import/cpan.scm (%metacpan-base-url): New variable.
(module-&gt;dist-name, cpan-fetch): Refer to it instead of the hard-coded URL.
* tests/cpan.scm ("cpan-&gt;guix-package"): Use 'with-http-server' instead
of 'mock'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-01-15 18:40:43 +0100'>2020-01-15</span></td><td><a href='/guix/commit/tests/cpan.scm?id=69f132554c6bd23df4610a21e636bde5f0578174'>import: cpan: Rewrite to use 'define-json-mapping'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/import/cpan.scm (&lt;cpan-dependency&gt;, &lt;cpan-release&gt;): New
JSON-mapped record types.
(metacpan-url-&gt;mirror-url): New procedure.
(cpan-source-url): Rewrite in terms of it.
(cpan-version): Remove.
(cpan-module-&gt;sexp): Rewrite to take a &lt;cpan-release&gt; instead of an
alist, and rename 'meta' to 'release'.
[convert-inputs]: Rewrite to use 'cpan-release-dependencies'.
Update calls to 'convert-inputs' to pass a list of symbols.
Replace 'assoc-ref' calls with the appropriate field accessors.
(cpan-&gt;guix-package): Rename 'module-meta' to 'release'.
(latest-release): Likewise, and use the appropriate accessors.
* tests/cpan.scm (test-json): Remove "prereqs" record; add "dependency"
list.
("source-url-http", "source-url-https"): Remove.
("metacpan-url-&gt;mirror-url, http")
("metacpan-url-&gt;mirror-url, https"): New tests.
</span></span></td><td>Ludovic Courtès</td></tr>