chore: import upstream snapshot with attribution

procmail/install_check.pl

@@ -0,0 +1,22 @@
+# install_check.pl
+
+do 'procmail-lib.pl';
+
+# is_installed(mode)
+# For mode 1, returns 2 if Procmail is installed and configured for use by
+# Webmin, 1 if installed but not configured, or 0 otherwise.
+# For mode 0, returns 1 if installed, 0 if not
+sub is_installed
+{
+# Check for procmail binary
+return 0 if (!&has_command($config{'procmail'}));
+if ($_[0]) {
+	# Check if configured too
+	local ($mod, $err) = &check_mailserver_config();
+	return $err ? 1 : 2;
+	}
+else {
+	return 1;
+	}
+}
+