[libclc] [libclc] Fix a couple of issues preventing in-tree builds (PR #87505)

[Fraser Cormack via cfe-commits]

frasercrmck wrote:

> This change broke standalone build against LLVM dylib — it now insists on linking to non-existing static libraries:
> 
> ```
> FAILED: prepare_builtins 
> : && /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -march=znver2 --param=l1-cache-size=32 --param=l1-cache-line-size=64 -O2 -pipe -frecord-gcc-switches -Wl,-O1 -Wl,--as-needed -Wl,--defsym=__gentoo_check_ldflags__=0     -Wl,-rpath-link,  -Wl,--gc-sections CMakeFiles/prepare_builtins.dir/utils/prepare-builtins.cpp.o -o prepare_builtins  -Wl,-rpath,"\$ORIGIN/../lib64:/usr/lib/llvm/17/lib64"  -lLLVMBitReader  -lLLVMBitWriter  -lLLVMCore  -lLLVMIRReader  /usr/lib/llvm/17/lib64/libLLVMSupport.a  -lrt  -ldl  -lm  /usr/lib64/libz3.so  /usr/lib64/libz.so  /usr/lib64/libzstd.so  /usr/lib64/libtinfo.so  /usr/lib/llvm/17/lib64/libLLVMDemangle.a && :
> /usr/lib/gcc/x86_64-pc-linux-gnu/13/../../../../x86_64-pc-linux-gnu/bin/ld: cannot find -lLLVMBitReader: No such file or directory
> /usr/lib/gcc/x86_64-pc-linux-gnu/13/../../../../x86_64-pc-linux-gnu/bin/ld: cannot find -lLLVMBitWriter: No such file or directory
> /usr/lib/gcc/x86_64-pc-linux-gnu/13/../../../../x86_64-pc-linux-gnu/bin/ld: cannot find -lLLVMCore: No such file or directory
> /usr/lib/gcc/x86_64-pc-linux-gnu/13/../../../../x86_64-pc-linux-gnu/bin/ld: cannot find -lLLVMIRReader: No such file or directory
> collect2: error: ld returned 1 exit status
> ```
> 
> Given that it apparently doesn't fix in-tree builds fully, please revert and let's figure out how to do it properly without breaking its primary use case.

Ach, sorry about that, thanks for catching that. It's tricky without CI to catch this kind of thing, though that was particularly silly of me. I actually struggled to build LLVM locally with the kind of configuration that only has dynamic libraries available to reproduce.

That said, I've pushed 8461d901a770516cf2069fe3bce979a6f8fc8d76 which should just re-instate the old behaviour for out-of-tree builds. If that doesn't fix the issue then I'll revert properly - please let me know, thanks.

https://github.com/llvm/llvm-project/pull/87505