gnu: Add Rubber.

* gnu/packages/texlive.scm (rubber): New variable.

Merge branch 'core-updates'

Merge branch 'xorg' into core-updates

gnu: Add X.org as input to Texlive.

* gnu/packages/texlive.scm (texlive): Add x.org inputs.

gnu: Rename module 'freetype' to the more general 'fontutils'.

* gnu/packages/freetype.scm: Rename file to...
* gnu/packages/fontutils.scm: ...this.
* Makefile.am (MODULES): Rename module.
* gnu/packages/{ghostscript,grub,pdf,texlive}.scm: Rename dependency.

gnu: texlive: Add input (t)csh.

* gnu/packages/texlive.scm (texlive): Add input tcsh.

gnu: Add TeXLive.

* gnu/packages/texlive.scm: New file.
* Makefile.am (MODULES): Add it.