bug #3206876 [core] Work without mbstring installed.

This is patch from upstream php-gettext, which will be included in next
release there.

ChangeLog

@@ -146,6 +146,7 @@
 - rfe #1312657 [dbi] Default to mysqli extension.
 - rfe #1168350 [interface] Add clear button to SQL edit box.
 - [core] Update library PHPExcel to version 1.7.6
+- bug #3206876 [core] Work without mbstring installed.
 
 3.3.10.0 (not yet released)
 - patch #3147400 [structure] Aria table size printed as unknown,

libraries/php-gettext/gettext.inc

@@ -174,14 +174,13 @@ function _get_codeset($domain=null) {
  * Convert the given string to the encoding set by bind_textdomain_codeset.
  */
 function _encode($text) {
+  $target_encoding = _get_codeset();
+  if (function_exists("mb_detect_encoding")) {
     $source_encoding = mb_detect_encoding($text);
-    $target_encoding = _get_codeset();
-    if ($source_encoding != $target_encoding) {
-        return mb_convert_encoding($text, $target_encoding, $source_encoding);
-    }
-    else {
-        return $text;
-    }
+    if ($source_encoding != $target_encoding)
+      $text = mb_convert_encoding($text, $target_encoding, $source_encoding);
+  }
+  return $text;
 }