diff --git a/src/tools/compiletest/src/command-list.rs b/src/tools/compiletest/src/command-list.rs
index 6735e9faa7a67..c356f4266f016 100644
--- a/src/tools/compiletest/src/command-list.rs
+++ b/src/tools/compiletest/src/command-list.rs
@@ -201,6 +201,7 @@ const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "only-wasm32-wasip1",
     "only-watchos",
     "only-windows",
+    "only-windows-gnu",
     "only-x86",
     "only-x86_64",
     "only-x86_64-fortanix-unknown-sgx",
diff --git a/src/tools/run-make-support/src/external_deps/cc.rs b/src/tools/run-make-support/src/external_deps/cc.rs
index 840bfa0d2b46e..19a89705acc1e 100644
--- a/src/tools/run-make-support/src/external_deps/cc.rs
+++ b/src/tools/run-make-support/src/external_deps/cc.rs
@@ -15,6 +15,13 @@ pub fn cc() -> Cc {
     Cc::new()
 }
 
+/// Construct a new platform-specific CXX compiler invocation.
+/// CXX_DEFAULT_FLAGS is passed from compiletest.
+#[track_caller]
+pub fn cxx() -> Cc {
+    Cc::new_cxx()
+}
+
 /// A platform-specific C compiler invocation builder. The specific C compiler used is
 /// passed down from compiletest.
 #[derive(Debug)]
@@ -44,6 +51,22 @@ impl Cc {
         Self { cmd }
     }
 
+    /// Construct a new platform-specific CXX compiler invocation.
+    /// CXX_DEFAULT_FLAGS is passed from compiletest.
+    #[track_caller]
+    pub fn new_cxx() -> Self {
+        let compiler = env_var("CXX");
+
+        let mut cmd = Command::new(compiler);
+
+        let default_cflags = env_var("CXX_DEFAULT_FLAGS");
+        for flag in default_cflags.split(char::is_whitespace) {
+            cmd.arg(flag);
+        }
+
+        Self { cmd }
+    }
+
     /// Specify path of the input file.
     pub fn input<P: AsRef<Path>>(&mut self, path: P) -> &mut Self {
         self.cmd.arg(path.as_ref());
diff --git a/src/tools/run-make-support/src/lib.rs b/src/tools/run-make-support/src/lib.rs
index a4bb9056346d9..085120764b463 100644
--- a/src/tools/run-make-support/src/lib.rs
+++ b/src/tools/run-make-support/src/lib.rs
@@ -44,7 +44,7 @@ pub use external_deps::{c_build, cc, clang, htmldocck, llvm, python, rustc, rust
 
 // These rely on external dependencies.
 pub use c_build::{build_native_dynamic_lib, build_native_static_lib};
-pub use cc::{cc, extra_c_flags, extra_cxx_flags, Cc};
+pub use cc::{cc, cxx, extra_c_flags, extra_cxx_flags, Cc};
 pub use clang::{clang, Clang};
 pub use htmldocck::htmldocck;
 pub use llvm::{
diff --git a/src/tools/tidy/src/allowed_run_make_makefiles.txt b/src/tools/tidy/src/allowed_run_make_makefiles.txt
index 36f7f68ef7b35..14e9a83b4c034 100644
--- a/src/tools/tidy/src/allowed_run_make_makefiles.txt
+++ b/src/tools/tidy/src/allowed_run_make_makefiles.txt
@@ -2,7 +2,6 @@ run-make/branch-protection-check-IBT/Makefile
 run-make/c-unwind-abi-catch-lib-panic/Makefile
 run-make/cat-and-grep-sanity-check/Makefile
 run-make/cdylib-dylib-linkage/Makefile
-run-make/compiler-rt-works-on-mingw/Makefile
 run-make/cross-lang-lto-clang/Makefile
 run-make/cross-lang-lto-pgo-smoketest/Makefile
 run-make/cross-lang-lto-upstream-rlibs/Makefile
@@ -20,8 +19,6 @@ run-make/foreign-double-unwind/Makefile
 run-make/foreign-exceptions/Makefile
 run-make/foreign-rust-exceptions/Makefile
 run-make/incr-add-rust-src-component/Makefile
-run-make/incr-foreign-head-span/Makefile
-run-make/interdependent-c-libraries/Makefile
 run-make/issue-35164/Makefile
 run-make/issue-36710/Makefile
 run-make/issue-47551/Makefile
diff --git a/tests/run-make/compiler-rt-works-on-mingw/Makefile b/tests/run-make/compiler-rt-works-on-mingw/Makefile
deleted file mode 100644
index 74917570a0142..0000000000000
--- a/tests/run-make/compiler-rt-works-on-mingw/Makefile
+++ /dev/null
@@ -1,9 +0,0 @@
-include ../tools.mk
-
-# only-windows-gnu
-
-all:
-	$(CXX) foo.cpp -c -o $(TMPDIR)/foo.o
-	$(AR) crus $(TMPDIR)/libfoo.a $(TMPDIR)/foo.o
-	$(RUSTC) foo.rs -lfoo -lstdc++
-	$(call RUN,foo)
diff --git a/tests/run-make/compiler-rt-works-on-mingw/rmake.rs b/tests/run-make/compiler-rt-works-on-mingw/rmake.rs
new file mode 100644
index 0000000000000..f1b41f96312de
--- /dev/null
+++ b/tests/run-make/compiler-rt-works-on-mingw/rmake.rs
@@ -0,0 +1,15 @@
+// `compiler-rt` ("runtime") is a suite of LLVM features compatible with rustc.
+// After building it was enabled on Windows-gnu in #29874, this test is a basic smoke test to
+// check if building and linking to it can work at all.
+// See https://github.com/rust-lang/rust/pull/29478
+
+//@ only-windows-gnu
+
+use run_make_support::{cxx, is_msvc, llvm_ar, run, rustc, static_lib_name};
+
+fn main() {
+    cxx().input("foo.cpp").arg("-c").out_exe("foo.o").run();
+    llvm_ar().obj_to_ar().output_input(static_lib_name("foo"), "foo.o").run();
+    rustc().input("foo.rs").arg("-lfoo").arg("-lstdc++").run();
+    run("foo");
+}
diff --git a/tests/run-make/incr-foreign-head-span/Makefile b/tests/run-make/incr-foreign-head-span/Makefile
deleted file mode 100644
index 9be4b0f601c30..0000000000000
--- a/tests/run-make/incr-foreign-head-span/Makefile
+++ /dev/null
@@ -1,21 +0,0 @@
-include ../tools.mk
-
-# ignore-none no-std is not supported
-# ignore-nvptx64-nvidia-cuda FIXME: can't find crate for 'std'
-
-# Ensure that modifying a crate on disk (without recompiling it)
-# does not cause ICEs in downstream crates.
-# Previously, we would call `SourceMap.guess_head_span` on a span
-# from an external crate, which would cause us to read an upstream
-# source file from disk during compilation of a downstream crate
-# See #86480 for more details
-
-INCR=$(TMPDIR)/incr
-
-all:
-	cp first_crate.rs second_crate.rs $(TMPDIR)
-	$(RUSTC) $(TMPDIR)/first_crate.rs  -C incremental=$(INCR) --target $(TARGET) --crate-type lib
-	$(RUSTC) $(TMPDIR)/second_crate.rs -C incremental=$(INCR) --target $(TARGET)  --extern first_crate=$(TMPDIR)/libfirst_crate.rlib --crate-type lib
-	rm $(TMPDIR)/first_crate.rs
-	$(RUSTC) $(TMPDIR)/second_crate.rs  -C incremental=$(INCR) --target $(TARGET) --cfg second_run --crate-type lib
-
diff --git a/tests/run-make/incr-foreign-head-span/rmake.rs b/tests/run-make/incr-foreign-head-span/rmake.rs
new file mode 100644
index 0000000000000..92e2ed5f8793a
--- /dev/null
+++ b/tests/run-make/incr-foreign-head-span/rmake.rs
@@ -0,0 +1,25 @@
+// Ensure that modifying a crate on disk (without recompiling it)
+// does not cause ICEs (internal compiler errors) in downstream crates.
+// Previously, we would call `SourceMap.guess_head_span` on a span
+// from an external crate, which would cause us to read an upstream
+// source file from disk during compilation of a downstream crate.
+// See https://github.com/rust-lang/rust/issues/86480
+
+//@ ignore-none
+// Reason: no-std is not supported
+//@ ignore-nvptx64-nvidia-cuda
+// Reason: can't find crate for 'std'
+
+use run_make_support::{rfs, rust_lib_name, rustc};
+
+fn main() {
+    rustc().input("first_crate.rs").incremental("incr").crate_type("lib").run();
+    rustc()
+        .input("second_crate.rs")
+        .incremental("incr")
+        .extern_("first_crate", rust_lib_name("first_crate"))
+        .crate_type("lib")
+        .run();
+    rfs::remove_file("first_crate.rs");
+    rustc().input("second_crate.rs").incremental("incr").cfg("second_run").crate_type("lib").run();
+}
diff --git a/tests/run-make/interdependent-c-libraries/Makefile b/tests/run-make/interdependent-c-libraries/Makefile
deleted file mode 100644
index 53a696d82bf12..0000000000000
--- a/tests/run-make/interdependent-c-libraries/Makefile
+++ /dev/null
@@ -1,15 +0,0 @@
-# ignore-cross-compile
-include ../tools.mk
-
-# The rust crate foo will link to the native library foo, while the rust crate
-# bar will link to the native library bar. There is also a dependency between
-# the native library bar to the natibe library foo.
-#
-# This test ensures that the ordering of -lfoo and -lbar on the command line is
-# correct to complete the linkage. If passed as "-lfoo -lbar", then the 'foo'
-# library will be stripped out, and the linkage will fail.
-
-all: $(call NATIVE_STATICLIB,foo) $(call NATIVE_STATICLIB,bar)
-	$(RUSTC) foo.rs
-	$(RUSTC) bar.rs
-	$(RUSTC) main.rs --print link-args
diff --git a/tests/run-make/interdependent-c-libraries/rmake.rs b/tests/run-make/interdependent-c-libraries/rmake.rs
new file mode 100644
index 0000000000000..ee8cc76c9ccbe
--- /dev/null
+++ b/tests/run-make/interdependent-c-libraries/rmake.rs
@@ -0,0 +1,21 @@
+// The rust crate foo will link to the native library foo, while the rust crate
+// bar will link to the native library bar. There is also a dependency between
+// the native library bar to the natibe library foo.
+// This test ensures that the ordering of -lfoo and -lbar on the command line is
+// correct to complete the linkage. If passed as "-lfoo -lbar", then the 'foo'
+// library will be stripped out, and the linkage will fail.
+// See https://github.com/rust-lang/rust/commit/e6072fa0c4c22d62acf3dcb78c8ee260a1368bd7
+
+//@ ignore-cross-compile
+// Reason: linkage still fails as the object files produced are not in the correct
+// format in the `build_native_static_lib` step
+
+use run_make_support::{build_native_static_lib, rustc};
+
+fn main() {
+    build_native_static_lib("foo");
+    build_native_static_lib("bar");
+    rustc().input("foo.rs").run();
+    rustc().input("bar.rs").run();
+    rustc().input("main.rs").print("link-args").run();
+}