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 5eeeb887444fa..19a89705acc1e 100644
--- a/src/tools/run-make-support/src/external_deps/cc.rs
+++ b/src/tools/run-make-support/src/external_deps/cc.rs
@@ -16,6 +16,7 @@ pub fn cc() -> Cc {
 }
 
 /// Construct a new platform-specific CXX compiler invocation.
+/// CXX_DEFAULT_FLAGS is passed from compiletest.
 #[track_caller]
 pub fn cxx() -> Cc {
     Cc::new_cxx()
@@ -51,6 +52,7 @@ impl Cc {
     }
 
     /// 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");
diff --git a/src/tools/tidy/src/allowed_run_make_makefiles.txt b/src/tools/tidy/src/allowed_run_make_makefiles.txt
index 114709cc3005e..14e9a83b4c034 100644
--- a/src/tools/tidy/src/allowed_run_make_makefiles.txt
+++ b/src/tools/tidy/src/allowed_run_make_makefiles.txt
@@ -19,7 +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/issue-35164/Makefile
 run-make/issue-36710/Makefile
 run-make/issue-47551/Makefile
diff --git a/tests/run-make/compiler-rt-works-on-mingw/rmake.rs b/tests/run-make/compiler-rt-works-on-mingw/rmake.rs
index 9bee91232ce66..f1b41f96312de 100644
--- a/tests/run-make/compiler-rt-works-on-mingw/rmake.rs
+++ b/tests/run-make/compiler-rt-works-on-mingw/rmake.rs
@@ -1,6 +1,6 @@
 // `compiler-rt` ("runtime") is a suite of LLVM features compatible with rustc.
-// After building it was enabled on Windows-gnu in #29874, this test checks
-// that compilation and execution with it are successful.
+// 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
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/rmake.rs b/tests/run-make/interdependent-c-libraries/rmake.rs
index cd3759d2d71d3..ee8cc76c9ccbe 100644
--- a/tests/run-make/interdependent-c-libraries/rmake.rs
+++ b/tests/run-make/interdependent-c-libraries/rmake.rs
@@ -6,7 +6,9 @@
 // library will be stripped out, and the linkage will fail.
 // See https://github.com/rust-lang/rust/commit/e6072fa0c4c22d62acf3dcb78c8ee260a1368bd7
 
-// FIXME(Oneirical): test-various
+//@ 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};