This is a follow-up of 7a1ba8df.

because re6stnet only supports OpenVPN 2.4.
This reverts commit 6802867d.

When compiling older GCC versions in newer machines, libsanitizer
does not compile, showing a error: `multiple definition of
'enum fsconfig_command'` (e.g.
https://github.com/llvm/llvm-project/issues/56421).
This is because starting from Glibc 2.36, it is not possible to include
both "linux/fs.h" and "sys/mount.h".

We can apply a patch, similar to the one in
https://reviews.llvm.org/D129471 , but with the extension and lines
changed to match the file. This is also similar to the upstream fix.

See merge request nexedi/slapos!1579

This will be used to add the sqlite3 binary directory to PATH.

See nexedi/neoppod@5923f8f5

This now supports producing html reports directly

nbd2-host and nbd2-port are asserted too.

Test are reorganized to easily assert mixed scenarios.

Zope no longer serve XML-RPC in ERP5, unless it is explicitly enabled
using this.

See erp5!1931

--enable-readline is broken:
  - it searches for readline.h instead of readline/readline.h
  - it does not abort when it fails to find headers
Use --with-readline-inc so that it sets HAVE_READLINE.

Also use the dedicated configure option to enable update limit.
And sqlite3 does not depend directly on ncurses.

See nexedi/neoppod@71564067

See merge request nexedi/slapos!1566

See merge request nexedi/slapos!1576

See merge request !1572

to avoid the following error:
relocation R_X86_64_32S against `.rodata' can not be used when making a shared object; recompile with -fPIC

software/osie-coupler: keep the build source directory instead of having another open62541-source part.

This is a fixup of 210e2d76.