* gnu/packages/tex.scm (texlive-fonts-amsfonts)[arguments]: Convert afm files
to tfm; also build missing tfm files via fontinst.
[native-inputs]: Replace texlive-fonts-cm, texlive-metafont-base, and
texlive-bin with a texlive-union of texlive-tex-fontinst-base,
texlive-fonts-cm, and texlive-metafont-base; add amsfonts-plain, amsfonts-map,
and amsfonts-afm.