TYPO3 Core

There are some ";" multiline header separators missing in the attachement boundary header parts in emails created by class t3lib_htmlmail with attachements.

Normally, this shouldn't be a serious issue but might prevent certain webmailers to recognize file types of attached files in emails sent by TYPO3 properly since they might not detect the filename (and ending) of the attachment at all.

Additionally, it would be nice if a pdf-attachement would be declared as Content-Type: application/pdf (currently application/octet-stream) for a more "reliable" reception (meaning to go more sure that pdf attachments aren't filtered for some security reason based on boundary header analysis).

... see attached patch, which adds some ";" and declares PDFs as application/pdf

(issue imported from #M8199)