Parse error: syntax error, unexpected T_ENDIF

if ( 'mystery' == $default )
		$default = "$host/avatar/ad516503a11cd5ca435acc9bb6523536?s={$size}"; // ad516503a11cd5ca435acc9bb6523536 == md5('[email protected]')
	elseif ( 'blank' == $default )
		$default = $email ? 'blank' : includes_url( 'images/blank.gif' );
	elseif ( !empty($email) && 'gravatar_default' == $default )
		$default = '';
	elseif ( 'gravatar_default' == $default )
		$default = "$host/avatar/?s={$size}";
	elseif ( empty($email) )
		$default = "$host/avatar/?d=$default&s={$size}";
	elseif ( strpos($default, 'https://') === 0 )
		$default = add_query_arg( 's', $size, $default );

	if ( !empty($email) ) {
		$out = "$host/avatar/";
		$out .= $email_hash;
		$out .= '?s='.$size;
		$out .= '&d=' . urlencode( $default );

		$rating = get_option('avatar_rating');
		if ( !empty( $rating ) )
			$out .= "&r={$rating}";

		$avatar = "<img alt='{$safe_alt}' src='{$out}' class='avatar avatar-{$size} photo' height='{$size}' width='{$size}' />";
	} else {
		$avatar = "<img alt='{$safe_alt}' src='{$default}' class='avatar avatar-{$size} photo avatar-default' height='{$size}' width='{$size}' />";
	}

	return apply_filters('get_avatar', $avatar, $id_or_email, $size, $default, $alt);
}
endif;

if ( !function_exists( 'wp_text_diff' ) ) :
/**
 * Displays a human readable HTML representation of the difference between two strings.
 *
 * The Diff is available for getting the changes between versions. The output is
 * HTML, so the primary use is for displaying the changes. If the two strings
 * are equivalent, then an empty string will be returned.
 *
 * The arguments supported and can be changed are listed below.
 *
 * 'title' : Default is an empty string. Titles the diff in a manner compatible
 *		with the output.
 * 'title_left' : Default is an empty string. Change the HTML to the left of the
 *		title.
 * 'title_right' : Default is an empty string. Change the HTML to the right of
 *		the title.
 *
 * @since 2.6
 * @see wp_parse_args() Used to change defaults to user defined settings.
 * @uses Text_Diff
 * @uses WP_Text_Diff_Renderer_Table
 *
 * @param string $left_string "old" (left) version of string
 * @param string $right_string "new" (right) version of string
 * @param string|array $args Optional. Change 'title', 'title_left', and 'title_right' defaults.
 * @return string Empty string if strings are equivalent or HTML with differences.
 */
function wp_text_diff( $left_string, $right_string, $args = null ) {
	$defaults = array( 'title' => '', 'title_left' => '', 'title_right' => '' );
	$args = wp_parse_args( $args, $defaults );

	if ( !class_exists( 'WP_Text_Diff_Renderer_Table' ) )
		require( ABSPATH . WPINC . '/wp-diff.php' );

	$left_string  = normalize_whitespace($left_string);
	$right_string = normalize_whitespace($right_string);

	$left_lines  = explode("\n", $left_string);
	$right_lines = explode("\n", $right_string);

	$text_diff = new Text_Diff($left_lines, $right_lines);
	$renderer  = new WP_Text_Diff_Renderer_Table();
	$diff = $renderer->render($text_diff);

	if ( !$diff )
		return '';

	$r  = "<table class='diff'>\n";
	$r .= "<col class='ltype' /><col class='content' /><col class='ltype' /><col class='content' />";

	if ( $args['title'] || $args['title_left'] || $args['title_right'] )
		$r .= "<thead>";
	if ( $args['title'] )
		$r .= "<tr class='diff-title'><th colspan='4'>$args[title]</th></tr>\n";
	if ( $args['title_left'] || $args['title_right'] ) {
		$r .= "<tr class='diff-sub-title'>\n";
		$r .= "\t<td></td><th>$args[title_left]</th>\n";
		$r .= "\t<td></td><th>$args[title_right]</th>\n";
		$r .= "</tr>\n";
	}
	if ( $args['title'] || $args['title_left'] || $args['title_right'] )
		$r .= "</thead>\n";

	$r .= "<tbody>\n$diff\n</tbody>\n";
	$r .= "</table>";

	return $r;

	endif;
}

Try swapping lines 1740 and 1741. That appears to be the difference between your file and the one on my server. Though I can’t be certain without the full file to reference. But 10 to 1, that is the issue.