gnu: texlive-latex-babel: Install to generic/babel.

* gnu/packages/tex.scm (texlive-latex-babel)[arguments]: Change tex-directory
to install to the "generic" tree.

gnu: texlive-union: Add texlive-generic-babel-english to defaults.

* gnu/packages/tex.scm (texlive-union): Add "texlive-generic-babel-english" to
the default inputs.

gnu: Add texlive-generic-babel-english.

* gnu/packages/tex.scm (texlive-generic-babel-english): New variable.

gnu: Add texlive-latex-cmap.

* gnu/packages/tex.scm (texlive-latex-cmap): New variable.

gnu: Add texlive-latex-fncychap.

* gnu/packages/tex.scm (texlive-latex-fncychap): New variable.

gnu: Add texlive-latex-expdlist.

* gnu/packages/tex.scm (texlive-latex-expdlist): New variable.

gnu: Add texlive-latex-eqparbox.

* gnu/packages/tex.scm (texlive-latex-eqparbox): New variable.

gnu: Add texlive-latex-draftwatermark.

* gnu/packages/tex.scm (texlive-latex-draftwatermark): New variable.

gnu: Add texlive-latex-dinbrief.

* gnu/packages/tex.scm (texlive-latex-dinbrief): New variable.

gnu: Add texlive-latex-blindtext.

* gnu/packages/tex.scm (texlive-latex-blindtext): New variable.

gnu: Add texlive-latex-polyglossia.

* gnu/packages/tex.scm (texlive-latex-polyglossia): New variable.

gnu: Add texlive-latex-supertabular.

* gnu/packages/tex.scm (texlive-latex-supertabular): New variable.

gnu: Add texlive-latex-geometry.

* gnu/packages/tex.scm (texlive-latex-geometry): New variable.

gnu: Add texlive-latex-gcite.

* gnu/packages/tex.scm (texlive-latex-gcite): New variable.

gnu: Add texlive-latex-galois.

* gnu/packages/tex.scm (texlive-latex-galois): New variable.

gnu: Add texlive-latex-g-brief.

* gnu/packages/tex.scm (texlive-latex-g-brief): New variable.

gnu: Add texlive-latex-amsrefs.

* gnu/packages/tex.scm (texlive-latex-amsrefs): New variable.

gnu: Add texlive-latex-acronym.

* gnu/packages/tex.scm (texlive-latex-acronym): New variable.

gnu: Add texlive-latex-preview.

* gnu/packages/tex.scm (texlive-latex-preview): New variable.

gnu: Add texlive-latex-ucs.

* gnu/packages/tex.scm (texlive-latex-ucs): New variable.