[Bug]: xcalc and xmessage abort: no font found

[b2jammer]

Problem description

xcalc and xmessage emit the following errors if used with termux-x11, but seem to work normally in TigerVNC (see termux/termux-packages#23002 (comment)):

Warning: Unable to load any usable ISO8859 font
Error: Aborting: no font found

What steps will reproduce the bug?

termux-x11 :0 &
export DISPLAY=:0
xcalc &
xmessage "Hello, world!" &

What is the expected behavior?

xcalc and xmessage should appear in the Termux X11 app.

[b2jammer]

So xcalc opens if termux-x11 is first run with an explicitly specified font path:

termux-x11 -fp $PREFIX/share/fonts :0 &
DISPLAY=:0 xcalc

How is the default font path obtained?

[RalfWerner]

After pkg up, I also had a font problem (#890) that I could solve:
In cd $PREFIX/X11 was an empty directory xkb, that I replace with the workaround rmdir xkb; ln -s ../xkeyboard-config-2/ xkb.