bug#19714: reftex under Xemacs 21.5.33 Mule

[Stephen J. Turnbull]

Uwe Brauer writes:

 > Debugger entered--Lisp error: (invalid-regexp "Invalid regular expression")
 >   
 > re-search-forward("\\(?:\\\\label{\\(?1:[^}]*\\)}\\|\\[[^]]*\\<label[[:space:]]*=[[:space:]]*{?\\(?1:[^],}]+\\)}?\\)\\|\\(^\\)[
 >     
 > ]*\\\\\\(begin{SaveListing}\\|part\\|chapter\\|section\\|subsection\\|subsubsection\\|paragraph\\|subparagraph\\|addchap\\|addsec\\)\\*?\\(\\[[^]]*\\]\\)?[[{
 >    
\n\\]\\|\\(^\\)[        ]*\\\\\\(include\\|input\\|subfile\\)[{         
]+\\([^}        \n
]+\\)\\|\\(^\\)[        
]*\\(\\\\appendix\\)\\|\\(\\\\glossary\\|\\\\index\\|\\\\nomenclature\\)[[{]" 
nil t)

It's the "\\(?1:" construct, which I have no idea what it is.

 > Debugger entered--Lisp error: (wrong-number-of-arguments 
 > define-obsolete-variable-alias 3)
 >   define-obsolete-variable-alias(reftex-toc-map reftex-toc-mode-map "24.1")

*sigh*  Gotta love the way the GNUbies whose whole point is software
freedom assume there's only one implementation of any given language.