Auto merge of #85554 - 12101111:fix-dedup-native-libs, r=petrochenkov

native lib: defer the duplicate check after relevant_lib check.

https://github.com/rust-lang/rust/pull/84794 break code using conditional-compilation with `#[link]` attributes.

```rust
#[cfg(target_env = "musl")]
cfg_if::cfg_if! {
    if #[cfg(any(target_feature = "crt-static", feature = "llvm-libunwind"))] {
        #[link(name = "unwind", kind = "static", modifiers = "-bundle")]
        extern "C" {}
    } else {
        #[link(name = "unwind", cfg(feature = "system-llvm-libunwind"))]
        #[link(name = "gcc_s", cfg(not(feature = "system-llvm-libunwind")))]
        extern "C" {}
    }
}

```

1 files changed, 8 insertions, 6 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index e330b5e703b..32275e9b073 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -1805,13 +1805,14 @@ fn add_local_native_libraries(
     let search_path = archive_search_paths(sess);
     let mut last = (NativeLibKind::Unspecified, None);
     for lib in relevant_libs {
-        // Skip if this library is the same as the last.
-        last = if (lib.kind, lib.name) == last { continue } else { (lib.kind, lib.name) };
-
         let name = match lib.name {
             Some(l) => l,
             None => continue,
         };
+
+        // Skip if this library is the same as the last.
+        last = if (lib.kind, lib.name) == last { continue } else { (lib.kind, lib.name) };
+
         let verbatim = lib.verbatim.unwrap_or(false);
         match lib.kind {
             NativeLibKind::Dylib { as_needed } => {
@@ -2144,9 +2145,6 @@ fn add_upstream_native_libraries(
     let mut last = (NativeLibKind::Unspecified, None);
     for &(cnum, _) in crates {
         for lib in codegen_results.crate_info.native_libraries[&cnum].iter() {
-            // Skip if this library is the same as the last.
-            last = if (lib.kind, lib.name) == last { continue } else { (lib.kind, lib.name) };
-
             let name = match lib.name {
                 Some(l) => l,
                 None => continue,
@@ -2154,6 +2152,10 @@ fn add_upstream_native_libraries(
             if !relevant_lib(sess, &lib) {
                 continue;
             }
+
+            // Skip if this library is the same as the last.
+            last = if (lib.kind, lib.name) == last { continue } else { (lib.kind, lib.name) };
+
             let verbatim = lib.verbatim.unwrap_or(false);
             match lib.kind {
                 NativeLibKind::Dylib { as_needed } => {