Fix undefined variables PHP Notice

- $order_string in include/dba
- $limit_string in include/dba
- $search in mod/search
- $lang_list in include/pgettext.php

include/dba.php

@@ -1145,6 +1145,7 @@ class dba {
 
 		$condition_string = self::buildCondition($condition);
 
+		$order_string = '';
 		if (isset($params['order'])) {
 			$order_string = " ORDER BY ";
 			foreach ($params['order'] AS $fields => $order) {
@@ -1157,6 +1158,7 @@ class dba {
 			$order_string = substr($order_string, 0, -2);
 		}
 
+		$limit_string = '';
 		if (isset($params['limit']) && is_int($params['limit'])) {
 			$limit_string = " LIMIT " . $params['limit'];
 		}

include/pgettext.php

@@ -19,12 +19,12 @@ require_once "include/dba.php";
  */
 function get_browser_language() {
 
+	$lang_list = [];
 	if (x($_SERVER, 'HTTP_ACCEPT_LANGUAGE')) {
 		// break up string into pieces (languages and q factors)
 		preg_match_all('/([a-z]{1,8}(-[a-z]{1,8})?)\s*(;\s*q\s*=\s*(1|0\.[0-9]+))?/i',
 			$_SERVER['HTTP_ACCEPT_LANGUAGE'], $lang_parse);
 
-		$lang_list = [];
 		if (count($lang_parse[1])) {
 			// go through the list of prefered languages and add a generic language
 			// for sub-linguas (e.g. de-ch will add de) if not already in array
@@ -41,8 +41,7 @@ function get_browser_language() {
 	}
 
 	// check if we have translations for the preferred languages and pick the 1st that has
-	for ($i = 0; $i < count($lang_list); $i++) {
-		$lang = $lang_list[$i];
+	foreach ($lang_list as $lang) {
 		if ($lang === 'en' || (file_exists("view/lang/$lang") && is_dir("view/lang/$lang"))) {
 			$preferred = $lang;
 			break;

mod/search.php

@@ -135,6 +135,7 @@ function search_content(App $a) {
 
 	Nav::setSelected('search');
 
+	$search = '';
 	if (x($a->data,'search'))
 		$search = notags(trim($a->data['search']));
 	else