[compiler-rt] Don't redefine LLVM_COMMON_CMAKE_UTILS if it's defined

[xry111]

If we are building compiler-rt inside llvm-x.y.z.src directory, we should not redefine LLVM_COMMON_CMAKE_UTILS.

[xry111]

@MaskRay Manually request for a review. It seems the bot does not @ a group for this change automatically.

[nikic]

LGTM, we do this everywhere else.

(I've encountered this as well, and ended up symlinking the directory to the right place. Thanks for actually fixing it...)

[MaskRay]

If we are building compiler-rt inside llvm-x.y.z.src directory, we should not redefine LLVM_COMMON_CMAKE_UTILS.

Can you add more instructions?

I can see that some subprojects checks DEFINED while libcxx/ doesn't check whether LLVM_COMMON_CMAKE_UTILS is defined

[xry111]

If we are building compiler-rt inside llvm-x.y.z.src directory, we should not redefine LLVM_COMMON_CMAKE_UTILS.

Can you add more instructions?

I can see that some subprojects checks DEFINED while libcxx/ doesn't check whether LLVM_COMMON_CMAKE_UTILS is defined

Extracting compiler-rt into llvm/projects/ and build:

tar xf llvm-17.0.1.src.tar.xz
tar xf cmake-17.0.1.src.tar.xz
mv cmake-17.0.1.src cmake
tar xf third-party-17.0.1.src.tar.xz
mv third-party-17.0.1.src third-party
tar xf compiler-rt-17.0.1.src.tar.xz
mv compiler-rt-17.0.1.src llvm-17.0.1.src/projects/compiler-rt
mkdir llvm-17.0.1.src/build
cd llvm-17.0.1.src/build
cmake ..

[xry111]

Ping. Do I need more explanation or some change?