* doc/symbols.xml doc/syms.xsl doc/checkapisym.xsl libxslt/libxslt.syms:
  the new symbol files, checking and stylesheets, based on libxml2 ones
* configure.in doc/Makefile.am libxslt/Makefile.am: modifications needed
  to activate the symbol versioning
* doc/libxslt-api.xml doc/libxslt-refs.xml doc/EXSLT/libexslt-api.xml
  doc/EXSLT/libexslt-refs.xml: regenerated
* libexslt/crypto.c libxslt/Makefile.am libxslt/keys.c libxslt/variables.c
  libxslt/xslt.c libxslt/xsltInternals.h libxslt/xsltlocale.c
  libxslt/xsltlocale.h: various cleanups