Need to check utf8_encode() is available before use.

[gitlost]

The DOM/XML extension isn't necessarily installed on some distros so use of utf8_encode() should be checked for availability first. It's not checked in wp_read_image_metadata() in "wp-admin/includes/image.php" (where I encountered its lack on a Ubuntu 16.04 PHP 7 server), introduced in [36429] and [36430], nor in wxr_cdata() in "wp-admin/includes/export.php", introduced in the distant past.

(Also it does ISO-8859-1 not Windows-1252 so more than likely not that good in the image situation anyway.)

[desrosj]

@gitlost are you interested in making a patch for this?

[gitlost]

Hi @desrosj yes, I'll give it a blast.