make x86_64-unknown-linux-gnu ubuntu again

[Emilgardis]

This pr effectively changes the default image for x86_64-unknown-linux-gnu to be ubuntu based.

We target 16.04 because that is what was used in cross 0.2.1.

While some users may not care about this, if GLIBC 2.23 is too new for someone, you're able to replace the image in Cross.toml with a CentOS based one (targets 2.17):

[target.x86_64-unknown-linux-gnu]
# The CentOS image gets published under the same package as the Ubuntu one, just with an added `-centos`
image = "ghcr.io/cross-rs/cross/x86_64-unknown-linux-gnu:main-centos"

Resolves #680

[Emilgardis]

bors try --target x86_64-unknown-linux-gnu

[bors]

try

Build succeeded:

• conclusion

[Emilgardis]

bors try --target powerpc-unknown-linux-gnu --target x86_64-unknown-linux-gnu.2.17

[Emilgardis]

that's annoying...

[Emilgardis]

bors cancel

[bors]

try

Build failed:

• conclusion

[Emilgardis]

bors try --target powerpc-unknown-linux-gnu --target x86_64-unknown-linux-gnu.2.17

[Emilgardis]

bors cancel

[bors]

try

Build failed:

• conclusion

[Emilgardis]

yq --output-format json '[.[] | select(.target + (if .sub then "." + .sub else "" end) == "powerpc-unknown-linux-gnu" or .target + (if .sub then "." + .sub else "" end) == "x86_64-unknown-linux-gnu.2.17")]' works on my machine, interesting...

[Emilgardis]

aha, yq is https://github.com/mikefarah/yq, not the python one

[Emilgardis]

bors try --target powerpc-unknown-linux-gnu --target x86_64-unknown-linux-gnu.2.17

[Emilgardis]

bors cancel

bash is not my friend

[Emilgardis]

bors try --target powerpc-unknown-linux-gnu --target x86_64-unknown-linux-gnu.2.17

[bors]

try

Already running a review

[bors]

try

Build failed:

• conclusion

[Emilgardis]

bors try --target powerpc-unknown-linux-gnu --target x86_64-unknown-linux-gnu.2.17

[Emilgardis]

bors cancel

bors try --target powerpc-unknown-linux-gnu --target x86_64-unknown-linux-gnu.2.17

[bors]

try

Already running a review

[Emilgardis]

bors cancel

will have to let it timeout I think...

[Emilgardis]

bors cancel

?

[Emilgardis]

bors try --target powerpc-unknown-linux-gnu --target x86_64-unknown-linux-gnu.2.17

[Emilgardis]

I'm not sure how to document it in the table. Maybe a new column or just a special entry with an asterisk

[Alexhuszagh]

I'm not sure how to document it in the table. Maybe a new column or just a special entry an asterisk

Something like this:

| Target                               |  libc  |   GCC   | C++ | QEMU  | `test` |
|--------------------------------------|-------:|--------:|:---:|------:|:------:|
| `x86_64-unknown-linux-gnu:centos` [5]  | 2.17   | 4.8.5   | ✓   | 4.2.1 |   ✓    |

[5] Must change `image = "x86_64-unknown-linux-gnu:centos"` in `Cross.toml` for `[target.x86_64-unknown-linux-gnu]` to use the CentOS7-compatible target.

[Emilgardis]

bors try --target x86_64-unknown-linux-gnu --target x86_64-unknown-linux-gnu.centos

this try will be unusually long as we don't have a cache for these

[Emilgardis]

are there anymore issues that this fixes?

[Alexhuszagh]

are there anymore issues that this fixes?

Just #680 I believe.

[Emilgardis]

I see one more thing to fix:

[bors]

try

Build succeeded:

• conclusion

[Emilgardis]

bors try --target x86_64-unknown-linux-gnu --target x86_64-unknown-linux-gnu.centos

[bors]

try

Build failed:

• conclusion

[Emilgardis]

canceled it early, but it should work

https://github.com/cross-rs/cross/runs/6889886219?check_suite_focus=true#step:2:125

edit: it does not :)

[Emilgardis]

bors try --target x86_64-unknown-linux-gnu --target x86_64-unknown-linux-gnu.centos

[Alexhuszagh]

bors r+

[bors]

try

Build succeeded:

• conclusion

[bors]

Build succeeded:

• conclusion