eplain packages with plain tex no longer have all needed definitions

If one uses tex rather than pdftex, one gets errors when inputting certain packages with eplain. For example, let test.tex be this file:

input /usr/share/texlive/texmf-dist/tex/eplain/eplain
beginpackages
   usepackage{graphicx}  
endpackages

bye

Running tex test.tex gives

This is TeX, Version 3.14159265 (TeX Live 2019/Debian) (preloaded format=tex)
(./test.tex (/usr/share/texlive/texmf-dist/tex/eplain/eplain.tex)
(/usr/share/texlive/texmf-dist/tex/plain/graphics-pln/miniltx.tex)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/graphicx.sty
(/usr/share/texlive/texmf-dist/tex/latex/graphics/keyval.sty)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/graphics.sty
(/usr/share/texlive/texmf-dist/tex/latex/graphics/trig.sty)
(/usr/share/texlive/texmf-dist/tex/latex/graphics-cfg/graphics.cfg)
(/usr/share/texlive/texmf-dist/tex/latex/graphics-def/dvips.def)
! Undefined control sequence.
l.118 protected
                defincludegraphics{%
? 
! Undefined control sequence.
l.171 edefGin@gzext{detokenize
                                 {gz}}
? 
! Undefined control sequence.
l.413 protected
                longdefrotatebox#1#2{%
? 
! Undefined control sequence.
l.482 protected
                defscalebox#1{%
? 
! Undefined control sequence.
l.501 protected
                defreflectbox{Gscale@box-1[1]}
? 
! Undefined control sequence.
l.502 protected
                defresizebox{%
? 
)
! Undefined control sequence.
l.239 protected
                defrotatebox{%
? 
) [1] )
Output written on test.dvi (1 page, 236 bytes).
Transcript written on test.log.

whereas running pdftex test.tex gives no errors:

This is pdfTeX, Version 3.14159265-2.6-1.40.20 (TeX Live 2019/Debian) (preloaded format=pdftex)
 restricted write18 enabled.
entering extended mode
(./test.tex (/usr/share/texlive/texmf-dist/tex/eplain/eplain.tex)
(/usr/share/texlive/texmf-dist/tex/plain/graphics-pln/miniltx.tex)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/graphicx.sty
(/usr/share/texlive/texmf-dist/tex/latex/graphics/keyval.sty)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/graphics.sty
(/usr/share/texlive/texmf-dist/tex/latex/graphics/trig.sty)
(/usr/share/texlive/texmf-dist/tex/latex/graphics-cfg/graphics.cfg)
(/usr/share/texlive/texmf-dist/tex/latex/graphics-def/pdftex.def)))
(/usr/share/texlive/texmf-dist/tex/context/base/mkii/supp-pdf.mkii
[Loading MPS to PDF converter (version 2006.09.02).]
) )
No pages of output.
Transcript written on test.log.

There were no problems with TeX Live 2015/Debian:

This is TeX, Version 3.14159265 (TeX Live 2015/Debian) (preloaded format=tex)
(./test.tex (/usr/share/texlive/texmf-dist/tex/eplain/eplain.tex)
(/usr/share/texlive/texmf-dist/tex/plain/graphics-pln/miniltx.tex)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/graphicx.sty
(/usr/share/texlive/texmf-dist/tex/latex/graphics/keyval.sty)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/graphics.sty
(/usr/share/texlive/texmf-dist/tex/latex/graphics/trig.sty)
(/usr/share/texlive/texmf-dist/tex/latex/latexconfig/graphics.cfg)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/dvips.def))) )
No pages of output.
Transcript written on test.log.

What is the proper fix for this?