rewrite link-cfg to rmake

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -25,7 +25,6 @@ run-make/libs-through-symlinks/Makefile
 run-make/libtest-json/Makefile
 run-make/libtest-junit/Makefile
 run-make/libtest-thread-limit/Makefile
-run-make/link-cfg/Makefile
 run-make/long-linker-command-lines-cmd-exe/Makefile
 run-make/long-linker-command-lines/Makefile
 run-make/macos-deployment-target/Makefile

tests/run-make/link-cfg/rmake.rs

@@ -0,0 +1,43 @@
+// The `#[link(cfg(..))]` annotation means that the `#[link]`
+// directive is only active in a compilation unit if that `cfg` value is satisfied.
+// For example, when compiling an rlib, these directives are just encoded and
+// ignored for dylibs, and all staticlibs are continued to be put into the rlib as
+// usual. When placing that rlib into a staticlib, executable, or dylib, however,
+// the `cfg` is evaluated *as if it were defined in the final artifact* and the
+// library is decided to be linked or not.
+// This test exercises this new feature by testing it with no dependencies, then
+// with only dynamic libraries, then with both a staticlib and dylibs. Compilation
+// and execution should be successful.
+// See https://github.com/rust-lang/rust/pull/37545
+
+//@ ignore-cross-compile
+// Reason: the compiled binary is executed
+
+use run_make_support::{bare_rustc, build_native_dynamic_lib, build_native_static_lib, run, rustc};
+
+fn main() {
+    build_native_dynamic_lib("return1");
+    build_native_dynamic_lib("return2");
+    build_native_static_lib("return3");
+    bare_rustc()
+        .print("cfg")
+        .target("x86_64-unknown-linux-musl")
+        .run()
+        .assert_stdout_contains("crt-static");
+    rustc().input("no-deps.rs").cfg("foo").run();
+    run("no-deps");
+    rustc().input("no-deps.rs").cfg("bar").run();
+    run("no-deps");
+
+    rustc().input("dep.rs").run();
+    rustc().input("with-deps.rs").cfg("foo").run();
+    run("with-deps");
+    rustc().input("with-deps.rs").cfg("bar").run();
+    run("with-deps");
+
+    rustc().input("dep-with-staticlib.rs").run();
+    rustc().input("with-staticlib-deps.rs").cfg("foo").run();
+    run("with-staticlib-deps");
+    rustc().input("with-staticlib-deps.rs").cfg("bar").run();
+    run("with-staticlib-deps");
+}