How to disable `mktexpk` in `dvips`?

Consider this ex-14-5.mf:

mode:=ljfour; % 600dpi for dvips (you must run "gftopk")
mode_setup;

beginchar("e",10pt#,7.5pt#,2.5pt#);
pickup pencircle scaled (.4pt+blacker);
draw fullcircle scaled .2w shifted (w/2,(h+d)/2-d);
draw fullcircle scaled .6w shifted (w/2,(h+d)/2-d);
draw fullcircle scaled w shifted (w/2,(h+d)/2-d);
endchar;

end

Run metafont on it. All is good:

$ mf ex-14-5
This is METAFONT, Version 2.7182818 (TeX Live 2017) (preloaded base=mf)
(ex-14-5.mf [101] )
Font metrics written on ex-14-5.tfm.
Output written on ex-14-5.600gf (1 character, 696 bytes).
Transcript written on ex-14-5.log.

Now run tex on this file. All is good:

fontx=ex-14-5 x e bye

$ tex ex-14-5
This is TeX, Version 3.14159265
(ex-14-5.tex [1] )
Output written on ex-14-5.dvi (1 page, 260 bytes).
Transcript written on ex-14-5.log.

When running dvips -M0 ex-14-5 it tries to create the pk file automatically:

This is dvips(k) 5.998 Copyright 2018 Radical Eye Software (www.radicaleye.com)
' TeX output 2019.03.14:1625' -> ex-14-5.ps

kpathsea: Running mktexpk --mfmode ljfour --bdpi 600 --mag 1+0/600 --dpi 600 ex-14-5
<various errors follow>

If I generate the pk file manually before calling dvips ex-14-5, all is OK:

$ rm *pk
$ gftopk ex-14-5.600gf
$ dvips ex-14-5
This is dvips(k) 5.998 Copyright 2018 Radical Eye Software (www.radicaleye.com)
' TeX output 2019.03.14:1625' -> ex-14-5.ps
<./ex-14-5.600pk></usr/share/texlive/texmf-dist/dvips/base/tex.pro>
</usr/share/texlive/texmf-dist/dvips/base/texps.pro>. 
</usr/share/texlive/texmf-dist/fonts/type1/public/amsfonts/cm/cmr10.pfb>[1] 

Except using -M0 command line option, I tried adding M0 to .dvipsrc – it does not help.

How to tell dvips not to attempt to generate pk file automatically?

fontx=./myfont

    /* If not an alias, try creating it on the fly with mktexpk,
       unless FONTNAME is absolute or explicitly relative.  */
    if (!ret && !kpathsea_absolute_p (kpse, fontname, true)) {

$ dvips -q ex-14-5
dvips: Font ./ex-14-5 not found; using cmr10
dvips: Design size mismatch in font ex-14-5
dvips: Checksum mismatch in font ex-14-5