Auto merge of #8141 - ehuss:uwp_support, r=ehuss

Uplift windows gnu DLL import libraries.

This is a repost of #6875, rebased with tests fixed.

Author: bors

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

@@ -257,6 +257,17 @@ impl TargetInfo {
                 flavor: FileFlavor::Normal,
                 should_replace_hyphens: false,
             })
+        } else if target_triple.ends_with("windows-gnu")
+            && crate_type.ends_with("dylib")
+            && suffix == ".dll"
+        {
+            // LD can link DLL directly, but LLD requires the import library.
+            ret.push(FileType {
+                suffix: ".dll.a".to_string(),
+                prefix: "lib".to_string(),
+                flavor: FileFlavor::Normal,
+                should_replace_hyphens: false,
+            })
         }
 
         // See rust-lang/cargo#4535.

tests/testsuite/build.rs

@@ -3810,8 +3810,7 @@ fn cdylib_final_outputs() {
         if cfg!(target_env = "msvc") {
             vec!["foo_bar.dll.lib", "foo_bar.dll"]
         } else {
-            // FIXME https://github.com/rust-lang/cargo/pull/6875
-            vec!["foo_bar.dll"]
+            vec!["foo_bar.dll", "libfoo_bar.dll.a"]
         }
     } else if cfg!(target_os = "macos") {
         vec!["libfoo_bar.dylib"]

tests/testsuite/build_script.rs

@@ -1663,7 +1663,6 @@ fn build_script_with_dynamic_native_dependency() {
                 let src = root.join(&file);
                 let dst = out_dir.join(&file);
                 fs::copy(src, dst).unwrap();
-                // FIXME https://github.com/rust-lang/cargo/pull/6875
                 if cfg!(target_env = "msvc") {
                     fs::copy(root.join("builder.dll.lib"),
                              out_dir.join("builder.dll.lib")).unwrap();

tests/testsuite/out_dir.rs

@@ -92,8 +92,7 @@ fn dynamic_library_with_debug() {
         &["libfoo.so"],
         &["libfoo.dylib"],
         &["foo.dll", "foo.dll.lib"],
-        // FIXME https://github.com/rust-lang/cargo/pull/6875
-        &["foo.dll"],
+        &["foo.dll", "libfoo.dll.a"],
     );
 }
 

tests/testsuite/plugins.rs

@@ -180,8 +180,7 @@ fn plugin_with_dynamic_native_dependency() {
                 let src = root.join(&file);
                 let dst = out_dir.join(&file);
                 fs::copy(src, dst).unwrap();
-                // FIXME https://github.com/rust-lang/cargo/pull/6875
-                    if cfg!(target_env = "msvc") {
+                if cfg!(target_env = "msvc") {
                     fs::copy(root.join("builder.dll.lib"),
                              out_dir.join("builder.dll.lib")).unwrap();
                 }