e48da1e38c
Add `-rtlib=compiler-rt` linker flags for the Clang 13 CI build. Clang 13 generates calls to __muloti4 (a 128-bit overflow-checked multiplication intrinsic) for signed 64-bit multiplication with overflow detection. This symbol is provided by LLVM's compiler-rt but is missing from GNU's libgcc, which is the default runtime library on Ubuntu. Related issues: - https://github.com/llvm/llvm-project/issues/14841 - https://github.com/abseil/abseil-cpp/issues/841 - https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=244169 PiperOrigin-RevId: 860529686 Change-Id: If58dc0328aa1dd87aef8ea02da555f57ad96b02c