[NTG-pdftex] Error with \pdfglyphtounicode when surrogates are involved.

[Karl Berry]

Hi Ross,

    \pdfglyphtounicode{Z}{D835DC81}   % MATH bold-italic-Z U+1D481 (U+D835 U+DC81)
    Z $Z$
    ...
    viz.
    <5A> <36E537DC81>
    instead of the intended:
    <5A> <D835DC81>

Call me stupid, but I don't understand why the glyphtounicode value
does not apply to the text `Z' as well as the math `Z'. The glyph name
in cmr10 is /Z just as in cmmi10. Can you, or anyone, elucidate?

(I realize you're reporting a separate bug, that the value gets
misinterpreted.) --thanks, karl.