The library build status is accessible from https://conan.compiler-explorer.com/

build prerequisites

The buildprocess of libraries (started by https://github.com/compiler-explorer/infra/blob/main/admin-daily-builds.sh) has a couple of safeguards to not build libraries allday everyday, namely:

The compiler needs to have supportBinary=true on in the current https://github.com/compiler-explorer/compiler-explorer/blob/main/etc/config/c%2B%2B.amazon.properties
If all libraries are being built, only a commit hash change will result in a new build.
If a particular compiler has failed to produce a valid build, it will be marked and will not build the library with this compiler anymore.
There are a couple of hardcoded exceptions that never attempt the build, these can be found in https://github.com/compiler-explorer/infra/blob/main/bin/lib/library_builder.py#L29
You can manually trigger a forced-build, by setting the --build-for=compilerid parameter, which can also be set by changing the 2nd parameter here -> https://github.com/compiler-explorer/infra/blob/main/admin-daily-builds.sh#L104
If you want to trigger all compilers to rebuild a certain library, you will need to manually delete the logging related to this library.

manually delete logging

You have to login to the conan instance and delete records from the sqlite database responsible for keeping the logging.

Example:

ce conan login
sudo -u ce sqlite3 /home/ce/.conan_server/buildslogs.db
delete from latest where library='unifex' and success=0;