Fix remaining uses of hardcoded /tmp to get the socket paths

Fixes #1097

src/file.cc

@@ -133,6 +133,15 @@ String compact_path(StringView filename)
     return filename.str();
 }
 
+StringView tmpdir()
+{
+    StringView tmpdir = getenv("TMPDIR");
+    if (not tmpdir.empty())
+        return tmpdir.back() == '/' ? tmpdir.substr(0_byte, tmpdir.length()-1)
+                                    : tmpdir;
+    return "/tmp";
+}
+
 bool fd_readable(int fd)
 {
     fd_set  rfds;

src/file.hh

@@ -24,6 +24,8 @@ String parse_filename(StringView filename);
 String real_path(StringView filename);
 String compact_path(StringView filename);
 
+StringView tmpdir();
+
 // returns pair { directory, filename }
 std::pair<StringView, StringView> split_path(StringView path);
 

src/main.cc

@@ -761,8 +761,10 @@ int main(int argc, char* argv[])
         const bool clear_sessions = (bool)parser.get_switch("clear");
         if (list_sessions or clear_sessions)
         {
-            StringView username = getpwuid(geteuid())->pw_name;
+            const StringView username = getpwuid(geteuid())->pw_name;
-            for (auto& session : list_files(format("/tmp/kakoune/{}/", username)))
+            const StringView tmp_dir = tmpdir();
+            for (auto& session : list_files(format("{}/kakoune/{}/", tmp_dir,
+                                                   username)))
             {
                 const bool valid = check_session(session);
                 if (list_sessions)
@@ -770,7 +772,8 @@ int main(int argc, char* argv[])
                 if (not valid and clear_sessions)
                 {
                     char socket_file[128];
-                    format_to(socket_file, "/tmp/kakoune/{}/{}", username, session);
+                    format_to(socket_file, "{}/kakoune/{}/{}", tmp_dir,
+                              username, session);
                     unlink(socket_file);
                 }
             }

src/remote.cc

@@ -480,15 +480,6 @@ void RemoteUI::set_ui_options(const Options& options)
     m_socket_watcher.events() |= FdEvents::Write;
 }
 
-static StringView tmpdir()
-{
-    StringView tmpdir = getenv("TMPDIR");
-    if (not tmpdir.empty())
-        return tmpdir.back() == '/' ? tmpdir.substr(0_byte, tmpdir.length()-1)
-                                    : tmpdir;
-    return "/tmp";
-}
-
 static sockaddr_un session_addr(StringView session)
 {
     sockaddr_un addr;