Some user distros do not use standard triplets, but instead, the triplet has another name.
Move the triplet name into a gitignored config file,
and fix a few trivial error messages breaking a cross-compile build:
- use headers-generic instead of headers-$arch
- if ulimit isn't set, don't do it.

Signed-off-by: jpsollie <janpieter.sollie@edpnet.be>

Allow the tests to run on a non-ABI-compatible cpu,
verify code when the architecture isn't physically available.
in the future, bcachefs-tools should be cross-compiled,
and the list of CPU types should be expanded

Signed-off-by: jpsollie <janpieter.sollie@edpnet.be>

Due to bcachefs being mainlined,
it's worth considering a more recent update channel,
which may include bcachefs features in the future.

Necessary adjustments have been made for the packages,
but kernel requirements may still need some extra tweaks

Signed-off-by: jpsollie <janpieter.sollie@edpnet.be>

ktest: enable debian sid fallback

RISC-V is currently moving from debian-ports to debian,
in order to protect from unreleased architectures etc,
a fallback scenario is needed:
in case preconfigured settings do not work,
apply a default sid fallback

Signed-Off-By: jpsollie <janpieter.sollie@edpnet.be>

Ktest has now been expanded with cross-binary armv7 (hard float).
this should allow some testing on more legacy armv7 hardware,
which may still be present in NAS devices.
However, due to the nature of the ecosystem, a limit is in place:
- 3GB ram for 32 bit systems
- 4 CPUs for 32 bit systems
I think if you need more, you'd better think of going 64-bit.
These constraints allow the ARM emulator to run smoothly.

Signed-off-by:  jpsollie <janpieter.sollie@edpnet.be>

Make the rust compiler instsallable via rustup even though it's not in the vm yet.
This avoids rust compile errors on emulated CPUs,
rustup installs for host cpu kernel architecture instead of VM architecture.

Signed-off-by: jpsollie <janpieter.sollie@edpnet.be>

Whereas MIPS and MIPS64 are abandoned my manufacturer,
SPARC and POWER seem to be still alive,
and upcoming RISCV also deserves some attention,
so add those to the list of supported architectures.

Signed-off-by: Janpieter Sollie <janpieter.sollie@edpnet.be>

This commit fixes a _LOT_ of issues with the previous commits,
but at least there's one supported big endian architecture now,
which is capable of booting and running ktests: s390x

For unsupported architectures, a number of root_create features:
- enabled snapshot lookups for debian archives,
  in case of missing dependencies, it may still be in there
- enabled possibility to build the package from source,
  this is painful
- enabled the possibility during root_create to intervene,
  this is only available on unsupported architectures.

So far, it seems the qemu E6500 emulator for powerPC isn't stable,
and rustup doesn't know about sparc / sparc64,
so both are currently broken.

Re-organised the cross.conf file as the first one was a bit messy.

Signed-Off-by: Janpieter Sollie <janpieter.sollie@edpnet.be>

Rustup only has a limited number of architectures,
when the root_image we are creating isn't supported,
try to install the debian rustc compiler.
this will be older, but >95% of time, it should be ok.

Signed-off-by: Janpieter Sollie <janpieter.sollie@edpnet.be>

- fix malfunctioning variables
- provide sid fallback for missing architectures
- make the extended installer default for sid

Signed-off-by: Janpieter Sollie <janpieter.sollie@edpnet.be>

when running tests, eg test1 on arch 1, and then on arch 2,
the whole bcachefs-tools package needs to be rebuilt:
all binaries of arch 1 need to be erased, and recompiled for arch 2
when going back to arch 1, it happens again

This patch fixes the issue by applying a arch-specific overlay,
so bcachefs-tools doesn't need a full rebuild every time.
The overlay is mounted via fuse-overlay.
If this isn't available, it will fall back to rsync,
causing a larger waste of disk space,
and not-applied-immediately git commits.

Signed-of-by: jpsollie <janpieter.sollie@edpnet.be>