This was intentional on my part. This patch does not attempt to make Clang a 'first-class' supported toolchain in BSL, it is expected that Clang will still be treated as 'GNU-like'. Setting BSLS_PLATFORM_CMP_VERSION using the __clang_major__/__clang_minor__ macros but leaving BSLS_PLATFORM_CMP_GNU set would likely result in much of the platform-specific code in bsls_platform failing to compile as it would believe that the compiler is an old GNU compiler.

This patch leaves *both* BSLS_PLATFORM_CMP_GNU and BSLS_PLATFORM_CMP_CLANG set, as they were previously. The compiler version macro is then set to ensure that code expecting a GNU compiler will behave appropriately, as Clang emulates the GNU compiler.

If you'd prefer BSLS_PLATFORM_CMP_VERSION to be based on the __clang_*__ macros, do you have any suggestions as to how ensure the rest of the platform code continues to compile and operate correctly?