>>>>> On Wed, 18 Mar 2020 20:18:11 +0200, Eli Zaretskii <eliz@gnu.org> said:

    >> From: Robert Pluim <rpluim@gmail.com>
    >> Cc: sorganov@gmail.com,  handa@gnu.org,  40097@debbugs.gnu.org
    >> Date: Wed, 18 Mar 2020 17:28:47 +0100
    >> 
    >> ftfont.c:
    >> 
    >> { "windows-1251", { 0x0401, 0x0490 }, "ru"},
    >> 
    >> Thread 1 "emacs" hit Breakpoint 3, ftfont_get_charset (registry=XIL(0x394540)) at ftfont.c:486
    >> 486	  for (i = j = 0; i < SBYTES (SYMBOL_NAME (registry)); i++, j++)
    >> (gdb) pp registry
    >> microsoft-cp1251
    >> (gdb) 
    >> 
    >> So correcting the name of the registry in ftfont.c fixes this.

    Eli> You mean, fixing that makes DejaVu Sans Mono be used in this case?

Yes.

    Eli> That's great, let's fix this in emacs-27 then.

If you want me to be conservative, I could *add* a microsoft-cp1251
entry instead of replacing windows-1251, but as far as I know
windows-1251 is not a valid registry name.