I find this a little easier to read and understand.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

… building runtimes

In the instrumented stage of the LLVM build when performing PGO, we set
LLVM_BUILD_RUNTIME to OFF, as recommended by the LLVM documentation:

https://llvm.org/docs/HowToBuildWithPGO.html#building-clang-with-pgo

This breaks adding 'profile' to the distribution components, which was
done in ClangBuiltLinux#243, as shown by the following cmake error:

  $ build-llvm.py \
        --llvm-folder . \
        --pgo kernel-defconfig \
        --projects clang compiler-rt lld \
        --targets X86
  ...
  CMake Error at cmake/modules/LLVMDistributionSupport.cmake:276 (message):
    Specified distribution component 'profile' doesn't have an install target
  Call Stack (most recent call first):
    CMakeLists.txt:1340 (llvm_distribution_add_targets)

  CMake Error at cmake/modules/LLVMDistributionSupport.cmake:284 (message):
    Specified distribution component 'profile' doesn't have an install-stripped
    target.  Its installation target creation should be changed to use
    add_llvm_install_targets, or you should manually create the
    'install-profile-stripped' target.
  Call Stack (most recent call first):
    CMakeLists.txt:1340 (llvm_distribution_add_targets)

compiler-rt is only included when LLVM_BUILD_RUNTIME is ON, so don't
include the 'llvm-profdata' and 'profile' targets when
LLVM_BUILD_RUNTIME is OFF.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>