note: updating to a more recent version would require more changes
because now jetty must have a certificate matching the hostname, see
https://github.com/metabase/metabase/issues/29660#issuecomment-1496625318

Since go1.18 is no longer supported, we should switch to a newer
version (("Each major Go release is supported until there are two
newer major releases" [1]).

[1] https://go.dev/doc/devel/release

/reviewed-by @kirr
/reviewed-on nexedi/slapos!1417

We should upgrade to Go 1.20, because Go 1.18 is already no longer supported.
("Each major Go release is supported until there are two newer major releases" [1]).
Go 1.20 is the incremental improvement for earlier go 1.19 release.
We skip Go 1.19, because it's also unsupported as soon as Go 1.21 is
released (this is expected to happen in one month [2]).

Please find all details in the official release note:

    https://go.dev/doc/go1.20

It was released on 2023-02-01 [1]. Due to the go promise of compatibility
most software should still compile without any problems.

We need to differentiate between go before 1.19 and go after 1.19, because
go before 1.19 needs TestSCMCredentials patch, while starting from go
1.19 this patch has been applied upstream [3].

[1] https://go.dev/doc/devel/release
[2] https://tip.golang.org/doc/go1.21
[3] https://github.com/golang/go/commit/f839aaa22b66bc556fac72f7396082212d2ef45d

/reviewed-by @kirr
/reviewed-on nexedi/slapos!1417

See merge request nexedi/slapos!1415

Forward enb.xlog to another fluentd or fluentbit server using fluentd's
forward protocol.

Currently, TLS is enabled and a pre-shared secret key is used for
authentication, but certificate verification is disabled.

Since the wendelin.core 2.alpha3 release 9 month ago, new fixes
were added to wendelin.core, which we would like to have in SlapOS.
One very important new feature is that this wendelin.core version now
support golang 1.20, so with this we can easily proceed to upgrade our
default golang version.

/reviewed-by @kirr
/reviewed-on nexedi/slapos!1416

without this cleanup, the software integration tests of KVM were stuck
forever because unittest was waiting for the subprocess to stop.

if '-ltinfo', '-ltermcap' or '-lcurses' is set in the linker option,
sqlite3 binary wil link to system libtinfo like this:

slapsoft@tomo-node:~/shared/sqlite3/39068f3749274fa37ab3897081678816/.build/sqlite-autoconf-3370200$ ldd sqlite3
	linux-vdso.so.1 (0x00007fff6dfe6000)
	libreadline.so.8 => /opt/slapgrid/shared/readline/13387ca15e2015da77fab391a268aaa6/lib/libreadline.so.8 (0x00007f4418d7d000)
	libtinfo.so.6 => /lib/x86_64-linux-gnu/libtinfo.so.6 (0x00007f4418d40000)
	libz.so.1 => /opt/slapgrid/shared/zlib/ac3692dceab375c8e6b9c06735e5faf2/lib/libz.so.1 (0x00007f4418d1b000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f4418bd7000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f4418bd1000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f4418bad000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f44189d9000)
	libncurses.so.6 => /opt/slapgrid/shared/ncurses/13a31fd4ae4eaba4a72e42f42c997f1c/lib/libncurses.so.6 (0x00007f441897c000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f4418f5a000)

if libuuid was present on the system, python would link with it in:
lib/python3.9/lib-dynload/_uuid.cpython-39-x86_64-linux-gnu.so

if libtinfo was present on the system, readline would prefer to use it instead of libncurses

This will let a non-shared Theia (for example coming from shacache
binary) to be able to use the shared parts of a machine.

See merge request nexedi/slapos!1409

See merge request nexedi/slapos!1407

See merge request !1399

Fix takoever of a theia with initial embedded instance. The issue was
that the promise checking that the embedded instance was successfully
requested relied on files which were not transferred to backup theia.

The location of these files has been changed in order to transfer them;
therefore the old location is still checked for upgrade-compatibility.

Test that takeover of theia with an initial embedded instance succeeds.