gnu: Add texlive-yafoot.

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

gnu: Add texlive-xytree.

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

gnu: Add texlive-xwatermark.

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

gnu: Add texlive-xurl.

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

gnu: Add texlive-xtab.

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

gnu: Add texlive-xsim.

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

gnu: Add texlive-xsavebox.

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

gnu: Add texlive-xprintlen.

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

gnu: Add texlive-xpeek.

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

gnu: Add texlive-xpunctuate.

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

gnu: Add texlive-xoptarg.

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

gnu: Add texlive-xnewcommand.

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

gnu: Add texlive-xltabular.

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

gnu: Add texlive-xkcdcolors.

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

gnu: Add texlive-xint.

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

gnu: Add texlive-xhfill.

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

gnu: Add texlive-xfakebold.

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

gnu: Add texlive-xellipsis.

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

gnu: Add texlive-xdoc.

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

gnu: Add texlive-xcpdftips.

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