Después de actualizar los paquetes (en Miktex), ya casi nada se compila. Por ejemplo:
\documentclass{article}
\usepackage{libertine}
\begin{document}
plop
\end{document}
produce los siguientes errores:
C:\Users\TL\AppData\Roaming\MiKTeX\2.9\tex\latex\libertine\libertine.sty:10: Undefined control sequence. [\ifxetex]
C:\Users\TL\AppData\Roaming\MiKTeX\2.9\tex\latex\libertine\libertine.sty:12: Extra \else. [\else]
C:\Users\TL\AppData\Roaming\MiKTeX\2.9\tex\latex\libertine\libertine.sty:12: Undefined control sequence. [\else\ifluatex]
C:\Users\TL\AppData\Roaming\MiKTeX\2.9\tex\latex\libertine\libertine.sty:14: Extra \else. [\else]
C:\Users\TL\AppData\Roaming\MiKTeX\2.9\tex\latex\libertine\libertine.sty:16: Extra \fi. [\fi]
C:\Users\TL\AppData\Roaming\MiKTeX\2.9\tex\latex\libertine\libertine.sty:16: Extra \fi. [\fi\fi]
C:\Users\TL\AppData\Roaming\MiKTeX\2.9\tex\latex\libertine\libertine.sty:289: Undefined control sequence. [ \defaultfontfeatures]
C:\Users\TL\AppData\Roaming\MiKTeX\2.9\tex\latex\libertine\libertine.sty:290: LaTeX Error: Missing \begin{document}. [ L]
C:\Users\TL\AppData\Roaming\MiKTeX\2.9\tex\latex\libertine\libertine.sty:296: Undefined control sequence. [ \setmainfont]
Sin embargo, el paqueteiftexestá instalado y no hayifxetexpaquete para descargar. Parecesiptexproporciona \ifXeTeX, no ifxetex(¡en serio!?!...). Surgen problemas similares para \ifluatex.
Cómo arreglar esto ?