Clang LTO PR Submitted For Linux 5.12, But x86_64 Support Not Included Yet

The pull request is pending that would allow Clang Link-Time Optimizations (LTO) to be enabled when building the Linux 5.12 kernel with this alternative compiler. The initial pull request has the compiler optimization work ready for the core infrastructure and 64-bit ARM (AArch64) while the x86_64 support isn't expected until the Linux 5.13 cycle...