Prompted by CVE-2021-3541, but this includes an awful lot of serious bug
fixes by Nick and others.
- configure.ac: bumped to new release
- doc/* updated and regenerated
In Windows 64 a socket is no more represented by an int,
this breaks the nanoftp API and nanoftp/nanohttp, the patch
changes this and fix the API for Win64
Regenerated the XML and documentation as a result too.
* libxml.spec.in doc/devhelp/*: finished the integration with
devhelp, completing the index and inserted into the gtk-doc
database at "make install" stage
Daniel