[NTG-context] LMTX: request for \tracinglostchars=3

[Leah Neukirchen]

Hi,

since TeX Live 2021 (TeX 3.141592653), there is

> - if \tracinglostchars >= 3, make missing characters an error (not just
>   a log message), and always report the character code in hex.

LaTeX also enables this by default these days.

LMTX only seems to support =0 (ignore) and =1 (report).  Making these
a fatal error (with exit status != 0) would be useful for automated
typesetting, as missing characters easily can get lost in the logs,
and then symbols are missing unnoticed in the output.

(However, \tracinglostchars=3 also doesn't seem to work with
LuaTeX+MKIV, probably because there is code to fallback to other fonts?)

cu,
-- 
Leah Neukirchen  <leah at vuxu.org>  https://leahneukirchen.org/