bug#28242: Batch mode compiling: Error messages are displayed with "invalid character" glyph bounding symbols.

[Eli Zaretskii]

> Date: Sun, 27 Aug 2017 09:16:54 +0000
> From: Alan Mackenzie <acm@muc.de>
> Cc: 28242@debbugs.gnu.org
> 
> Why are these curly quotes being output without first checking that the
> device they're being output to can display them?

Paul, is it possible to use for this purpose a technique similar to
what you coded in calculate_glyph_code_table?  That is, call that
special ioctl function, then look in the mapping it returns for the
curly quote characters, and if they aren't there, reset
text_quoting_flag?  Would that work?