After updating packages (on Miktex), almost nothing compiles anymore. For example:
\documentclass{article}
\usepackage{libertine}
\begin{document}
plop
\end{document}
results in the following errors:
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]
However, the package iftex is installed, and there is no ifxetex package to download. Seems like ifptex provides \ifXeTeX, not ifxetex (seriously !?!...). Similar problems arise for \ifluatex.
How to fix this ?
iftexpackage was updated a few months (weeks?) ago, and now bothifxetexandifluatex(and a couple others) just loadiftex. I'd guess that you updated theifxetexpackage but notiftex. Check that, and also “make sure you update in both user and admin modes” – Phelype Oleinik Dec 05 '19 at 00:02iftexdirectory inLocalTeXMF/tex/latex(the distribution installs it intex/generic). – Bernard Dec 05 '19 at 00:42