Revert accidental change.

Doc/lib/libctypes.tex

 \ifx\locallinewidth\undefined\newlength{\locallinewidth}\fi
-%\setlength{\locallinewidth}{\linewidth}
+\setlength{\locallinewidth}{\linewidth}
 \section{\module{ctypes} --- A foreign function library for Python.}
 \declaremodule{standard}{ctypes}
 \moduleauthor{Thomas Heller}{theller@python.net}