git clone error and more - trying OpenSpace compile on Raspberry Pi

An initial trial - just to see what breaks - trying to git clone OpenSpace and build it on a Raspberry Pi 4.

cloning into 'OpenSpace'...

error: RPC failed; HTTP 408 curl 22 The requested URL returned error: 408

fatal: expected 'packfile'

Apparently, this was due to an apt upgrade happening in another terminal window. Tried again later, and the git clone succeeded.

Now the error is during the generation of cmake files, regarding not finding gcc-13 - compiling gcc may take 6 hours.

https://forums.raspberrypi.com/viewtopic.php?t=362502

some post says don't cross compile.

https://gcc.gnu.org/install/
make bootstrap-lean to use less disk space.

Maybe I'll first try on a github runner to look out for ARM errors - 

https://github.blog/news-insights/product-news/arm64-on-github-actions-powering-faster-more-efficient-build-systems/

"We expect to begin offering Arm runners for open source projects by the end of the year. "

https://docs.github.com/en/actions/using-github-hosted-runners/using-github-hosted-runners/about-github-hosted-runners#standard-github-hosted-runners-for-public-repositories

"The arm64 Linux runner is in public preview and subject to change."

libcef seems to be available for arm64, but some bugs for RPi

https://github.com/chromiumembedded/cef/issues/3803

Edit - arm64 build fails due to wrong CEF binary - will need to fork the project, make modifications ...