Link to zlib while cross-compiling LLVM on Haiku

PR #72696 enabled the option LLVM_ENABLE_ZLIB for the LLVM builds. On Haiku, zlib is linked as a shared library. When cross-compiling LLVM, rustbuild should be instructed to explicitly linking to libz.

src/librustc_llvm/build.rs

@@ -198,7 +198,7 @@ fn main() {
     } else if target.contains("windows-gnu") {
         println!("cargo:rustc-link-lib=shell32");
         println!("cargo:rustc-link-lib=uuid");
-    } else if target.contains("netbsd") {
+    } else if target.contains("netbsd") || target.contains("haiku") {
         println!("cargo:rustc-link-lib=z");
     }
     cmd.args(&components);