ci: do arm64 builds natively on TravisCI

[AWSjswinney]

Fixes #115

Build arm64 wheel on Travis CI in order to build natively, instead of cross compiling from x86_64. This fixes several problems with the Arm wheel. It makes use of arch: arm64-graviton2, which is currently only available on travis-ci.com. It is probably possible to build the project on travis-ci.org with arch: arm64 instead, but it will be significantly slower.

See #115 for more information.

[AWSjswinney]

After several iterations with the parts of the CI that are difficult to test locally, I think I have everything working correctly now. The only part left that I don't know how to test is the final deploy step.

The resulting wheel for arm64 bundles the openssl libraries with it. I started out using the openssl library from the container, but switched back to the version 1.1.1h downloaded from openssl.org because the version in the container has a bunch of other dynamic library dependencies that I didn't want to pull in with this wheel.

root@245a92c7a9d4:/# pip3 install /io/dist/cmake-3.18.2.post1.post1.dev0_gd193b7f-py3-none-manylinux2014_aarch64.whl
Processing /io/dist/cmake-3.18.2.post1.post1.dev0_gd193b7f-py3-none-manylinux2014_aarch64.whl
Installing collected packages: cmake
Successfully installed cmake-3.18.2.post1.post1.dev0-gd193b7f
root@245a92c7a9d4:/# cmake --version
cmake version 3.18.2

CMake suite maintained and supported by Kitware (kitware.com/cmake).
root@245a92c7a9d4:/# ldd /usr/local/lib/python3.8/dist-packages/cmake/data/bin/cmake
        linux-vdso.so.1 (0x0000ffff871c4000)
        libstdc++.so.6 => /lib/aarch64-linux-gnu/libstdc++.so.6 (0x0000ffff86fb2000)
        librt.so.1 => /lib/aarch64-linux-gnu/librt.so.1 (0x0000ffff86f9a000)
        libdl.so.2 => /lib/aarch64-linux-gnu/libdl.so.2 (0x0000ffff86f86000)
        libssl-2da213e1.so.1.1 => /usr/local/lib/python3.8/dist-packages/cmake/data/bin/../../../cmake.libs/libssl-2da213e1.so.1.1 (0x0000ffff86ec1000)
        libcrypto-cee860d4.so.1.1 => /usr/local/lib/python3.8/dist-packages/cmake/data/bin/../../../cmake.libs/libcrypto-cee860d4.so.1.1 (0x0000ffff86be2000)
        libpthread.so.0 => /lib/aarch64-linux-gnu/libpthread.so.0 (0x0000ffff86bb2000)
        libm.so.6 => /lib/aarch64-linux-gnu/libm.so.6 (0x0000ffff86b07000)
        libgcc_s.so.1 => /lib/aarch64-linux-gnu/libgcc_s.so.1 (0x0000ffff86ae2000)
        libc.so.6 => /lib/aarch64-linux-gnu/libc.so.6 (0x0000ffff86971000)
        /lib/ld-linux-aarch64.so.1 (0x0000ffff87194000)

[AWSjswinney]

@thewtex Can you take a look at this PR or mention someone else who can? Thanks!

[thewtex]

@AWSjswinney thanks again!

Looks good.

TravisCI.com was enabled, but now the repository needs to be enabled. @jcfr could you please enable at:

https://travis-ci.com/organizations/scikit-build/migrate

[jcfr]

Thanks for the note. Doing so now.

[jcfr]

I migrated all repos from scikit-build org to travis.com, let me know if you need anything else to move forward with this.

[thewtex]

I migrated all repos from scikit-build org to travis.com, let me know if you need anything else to move forward with this.

@jcfr thanks! Looks good.

@AWSjswinney could you please address @jcfr's inline comments?

[AWSjswinney]

I made the requested changes. Let me know if you see anything else you'd like changed.

[thewtex]

@AWSjswinney Thanks for the update.

TravisCI.com is running now -- it seems to have caught an issue:

docker: Error response from daemon: OCI runtime create failed: container_linux.go:349: starting container process caused "exec: "/io/scripts/docker-build.sh": stat /io/scripts/docker-build.sh: no such file or directory": unknown.

[AWSjswinney]

Ah, yes. That's why automated tests exist! I pushed another update.

[AWSjswinney]

Thanks! I look forward to seeing the published wheel in pypi!

[jcfr]

Thanks @thewtex and @AWSjswinney for working on this 🙏