[libcxxabi] Always link against libzircon for Fuchsia targets (#115910)

When using LTO, the deplibs mechanism is insufficient to ensure that
libzircon is always brought into the link prior to LTO code generation.
The general problem is discussed in depth in
https://github.com/llvm/llvm-project/issues/56070

To work around this, we can just provide libzircon as a link input.

GitOrigin-RevId: fac9fcd55245479d040dde3f5e9f4e169c30a0ec
1 file changed