Add implib to the stamp files

This was already done when targetting msvc, but it needs to be done for
all targets to allow rustc to link with shared libraries when using llvm
-l<dllname> is only supported by gcc, while llvm needs an import library
to link indirectly with a dll

Author: chouquette

src/cargo/core/compiler/build_context/target_info.rs

@@ -258,6 +258,17 @@ impl TargetInfo {
                 should_replace_hyphens: false,
             })
         }
+        else if target_triple.ends_with("windows-gnu")
+                && crate_type.ends_with("dylib")
+                && suffix == ".dll"
+        {
+            ret.push(FileType {
+                suffix: ".dll.a".to_string(),
+                prefix: "lib".to_string(),
+                flavor: FileFlavor::Normal,
+                should_replace_hyphens: false,
+            })
+        }
 
         // See rust-lang/cargo#4535.
         if target_triple.starts_with("wasm32-") && crate_type == "bin" && suffix == ".js" {