[llvm] [bolt] Add cmake c,cxx,asm,linker flags (PR #68358)

[via llvm-commits]

hiraditya wrote:

> The issue is that we don't want arbitrary flags being passed to BOLT runtime library build – they are configured to be freestanding. Specifically, runtime library shouldn't depend on host libgcc_s.

Ah i see `-ffreestanding` in bolt/runtime/CMakeLists.txt. Do we also need `-nostdlib and -nodefaultlibs` flags? I wonder why i get ` -lgcc -lgcc_s` in the link line.
 
> The proper solution would probably be along the lines of `LLVM_ENABLE_RUNTIMES`.

Makes sense. Do you have wip patches for this?


https://github.com/llvm/llvm-project/pull/68358