Database: Support backticks around field names when parsing a query for the field type.

Avoids an undefined index PHP warning by `dbDelta()`.

Props davidmosterd, ocean90.
See #20263.
Built from https://develop.svn.wordpress.org/trunk@37538


git-svn-id: http://core.svn.wordpress.org/trunk@37506 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/upgrade.php

@@ -2221,7 +2221,7 @@ function dbDelta( $queries = '', $execute = true ) {
 			if ( array_key_exists( $tablefield_field_lowercased, $cfields ) ) {
 
 				// Get the field type from the query.
-				preg_match("|".$tablefield->Field." ([^ ]*( unsigned)?)|i", $cfields[ $tablefield_field_lowercased ], $matches);
+				preg_match( '|`?' . $tablefield->Field . '`? ([^ ]*( unsigned)?)|i', $cfields[ $tablefield_field_lowercased ], $matches );
 				$fieldtype = $matches[1];
 				$fieldtype_lowercased = strtolower( $fieldtype );
 

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37537';
+$wp_version = '4.6-alpha-37538';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.