rewrite manual-link to rmake

Author: Oneirical

src/tools/run-make-support/src/lib.rs

@@ -321,6 +321,26 @@ pub fn count_regex_matches_in_files_with_extension(re: &regex::Regex, ext: &str)
     count
 }
 
+/// Builds a static lib (`.lib` on Windows MSVC and `.a` for the rest) with the given name.
+#[track_caller]
+pub fn build_native_static_lib(lib_name: &str) -> PathBuf {
+    let obj_file = if is_msvc() { format!("{lib_name}") } else { format!("{lib_name}.o") };
+    let src = format!("{lib_name}.c");
+    let lib_path = static_lib_name(lib_name);
+    if is_msvc() {
+        cc().arg("-c").out_exe(&obj_file).input(src).run();
+    } else {
+        cc().arg("-v").arg("-c").out_exe(&obj_file).input(src).run();
+    };
+    let mut obj_file = PathBuf::from(format!("{lib_name}.o"));
+    if is_msvc() {
+        obj_file.set_extension("");
+        obj_file.set_extension("obj");
+    }
+    llvm_ar().obj_to_ar().output_input(&lib_path, &obj_file).run();
+    path(lib_path)
+}
+
 /// Use `cygpath -w` on a path to get a Windows path string back. This assumes that `cygpath` is
 /// available on the platform!
 #[track_caller]

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -76,7 +76,6 @@ run-make/lto-linkage-used-attr/Makefile
 run-make/lto-no-link-whole-rlib/Makefile
 run-make/lto-smoke-c/Makefile
 run-make/macos-deployment-target/Makefile
-run-make/manual-link/Makefile
 run-make/min-global-align/Makefile
 run-make/missing-crate-dependency/Makefile
 run-make/mixing-libs/Makefile

tests/run-make/manual-link/Makefile

@@ -0,0 +1,16 @@
+// A smoke test for the `-l` command line rustc flag, which manually links to the selected
+// library. Useful for native libraries, this is roughly equivalent to `#[link]` in Rust code.
+// If compilation succeeds, the flag successfully linked the native library.
+// See https://github.com/rust-lang/rust/pull/18470
+
+//@ ignore-cross-compile
+// Reason: the compiled binary is executed
+
+use run_make_support::{build_native_static_lib, run, rustc};
+
+fn main() {
+    build_native_static_lib("bar");
+    rustc().input("foo.rs").arg("-lstatic=bar").run();
+    rustc().input("main.rs").run();
+    run("main");
+}