[CMake][ELF] Add -fno-semantic-interposition and -Bsymbolic-functions

Motivated by a recent rant on too slow clang (linking against libLLVM.so and libclang-cpp.so)
when building the Linux kernel, I just created a CMake patch ⚙ D102090 [CMake][ELF] Link libLLVM.so and libclang-cpp.so with -Bsymbolic-functions
which will add -fno-semantic-interposition and -Wl,-Bsymbolic-functions to our build.
(My x86 kernel defconfig build is at least 15% faster)

I have added some distribution packagers as reviewers. Sending this message to
attract more users.

Circling back on this. Two patches have landed and will benefit Clang
13 onwards.

⚙ D102090 [CMake][ELF] Link libLLVM.so and libclang-cpp.so with -Bsymbolic-functions [CMake][ELF] Link libLLVM.so and
libclang-cpp.so with -Bsymbolic-functions
(my Linux kernel build with the libLLVM.so and libclang-cpp.so clang
is more than 15%+ faster, presumably due to much fewer symbol lookups.
~90% fewer JUMP_SLOT dynamic relocations)

⚙ D102453 [CMake][ELF] Add -fno-semantic-interposition for GCC and Clang>=13 [CMake][ELF] Add
-fno-semantic-interposition for GCC and Clang>=13
(LLVM Compile-Time Tracker
measures 3~4% improvement when compiled with GCC!
the binary size is 2% smaller)