Add db_set_charset() support for PostgreSQL and change its implementation for 'mysql'

Author: narfbg

system/database/drivers/mysql/mysql_driver.php

@@ -147,7 +147,7 @@ public function db_select($database = '')
 	 * @param	string
 	 * @return	bool
 	 */
-	public function db_set_charset($charset, $collation)
+	protected function _db_set_charset($charset, $collation)
 	{
 		return function_exists('mysql_set_charset')
 			? @mysql_set_charset($charset, $this->conn_id)

system/database/drivers/postgre/postgre_driver.php

@@ -146,6 +146,19 @@ function db_select()
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * Set client character set
+	 *
+	 * @param       string
+	 * @return      bool
+	 */
+	protected function _db_set_charset($charset)
+	{
+		return (pg_set_client_encoding($this->conn_id, $charset) === 0);
+	}
+
+	// --------------------------------------------------------------------
+
 	/**
 	 * Database version number
 	 *

user_guide_src/source/changelog.rst

@@ -59,6 +59,7 @@ Release Date: Not Released
    -  Replaced the _error_message() and _error_number() methods with error(), that returns an array containing the last database error code and message.
    -  Improved version() implementation so that drivers that have a native function to get the version number don't have to be defined in the core DB_driver class.
    -  PostgreSQL driver now uses pg_version() to get the database version number, when possible.
+   -  Added db_set_charset() support for PostgreSQL.
 
 -  Libraries