I couldn't get the toolchain generator in bazelbuild/bazel-toolchains to work properly (it produces code that does not build under bazel 6.0.0), so instead I updated our existing toolchains repo to be more configurable.
More specifically, we just need the GCC and Java versions to be configurable, since our toolchain currently hard-codes GCC 5 / Java 8, while the Ubuntu 20.04 image needs GCC 9 / Java 11.
The clang/LLVM stuff should "just work" since it doesn't include any version-specific info in the paths; e.g. it just points to /usr/local/bin/clang.
I couldn't get the toolchain generator in bazelbuild/bazel-toolchains to work properly (it produces code that does not build under bazel 6.0.0), so instead I updated our existing toolchains repo to be more configurable.
More specifically, we just need the GCC and Java versions to be configurable, since our toolchain currently hard-codes GCC 5 / Java 8, while the Ubuntu 20.04 image needs GCC 9 / Java 11.
The clang/LLVM stuff should "just work" since it doesn't include any version-specific info in the paths; e.g. it just points to
/usr/local/bin/clang.