[compiler-rt] [Fuchsia][cmake] Avoid referencing cxx_shared in compiler-rt (PR #112257)

[Paul Kirth via llvm-commits]

ilovepi wrote:

> Does someone understand how the layering works for compiler-rt? Libc++ links against compiler-rt itself, so how can we depend on libc++ from compiler-rt?

Aren't the builtins the only dependency? IIRC builtins are special in the runtimes build, and is handled that way to break the cyclic dependency in the build graph. @petrhosek can speak more to that though.

https://github.com/llvm/llvm-project/pull/112257