The question was asked for 4.2 (see PDF font embedding in LibreOffice 4.2?) but I don’t get the same messages in 4.3.
The answer was :
The custom font embedding option is
still there under File > Properties >
Fonts tab[1] (same location as v4.1).
It sounds like you may be referring to
the option to embed the standard 14
PostScript fonts (File > Export as
PDF… > General tab > General sectionEmbed standard fonts option).
But I don’t see the “Embed standard fonts” option in LO 4.3. There’s only “Embed OpenDocument File.”