rewrite raw-dylib-custom-dlltool to rmake

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -119,7 +119,6 @@ run-make/profile/Makefile
 run-make/prune-link-args/Makefile
 run-make/raw-dylib-alt-calling-convention/Makefile
 run-make/raw-dylib-c/Makefile
-run-make/raw-dylib-custom-dlltool/Makefile
 run-make/raw-dylib-import-name-type/Makefile
 run-make/raw-dylib-link-ordinal/Makefile
 run-make/raw-dylib-stdcall-ordinal/Makefile

tests/run-make/raw-dylib-custom-dlltool/rmake.rs

@@ -0,0 +1,25 @@
+// Instead of using the default dlltool, the rust compiler can also accept a custom
+// command file with the -C dlltool flag. This test uses it to compile some rust code
+// with the raw_dylib Windows-exclusive feature, and checks that the output contains
+// the string passed from the custom dlltool, confirming that the default dlltool was
+// successfully overridden.
+// See https://github.com/rust-lang/rust/pull/109677
+
+//@ only-windows
+//@ only-gnu
+//@ needs-dlltool
+// Reason: this test specifically checks the custom dlltool feature, only
+// available on Windows-gnu.
+
+use run_make_support::{diff, rustc};
+
+fn main() {
+    let out = rustc()
+        .crate_type("lib")
+        .crate_name("raw_dylib_test")
+        .input("lib.rs")
+        .arg("-Cdlltool=script.cmd")
+        .run()
+        .stdout_utf8();
+    diff().expected_file("output.txt").actual_text("actual_text", out).run();
+}