Include all kinds of auxiliary crates in the up-to-date timestamp

This was previously only including ordinary `aux-build` crates, and not files
associated with the other three kinds of auxiliary crate.

src/tools/compiletest/src/header/auxiliary.rs

@@ -1,6 +1,8 @@
 //! Code for dealing with test directives that request an "auxiliary" crate to
 //! be built and made available to the test in some way.
 
+use std::iter;
+
 use crate::common::Config;
 use crate::header::directives::{AUX_BIN, AUX_BUILD, AUX_CODEGEN_BACKEND, AUX_CRATE};
 
@@ -20,6 +22,20 @@ pub(crate) struct AuxProps {
     pub(crate) codegen_backend: Option<String>,
 }
 
+impl AuxProps {
+    /// Yields all of the paths (relative to `./auxiliary/`) that have been
+    /// specified in `aux-*` directives for this test.
+    pub(crate) fn all_aux_path_strings(&self) -> impl Iterator<Item = &str> {
+        let Self { builds, bins, crates, codegen_backend } = self;
+
+        iter::empty()
+            .chain(builds.iter().map(String::as_str))
+            .chain(bins.iter().map(String::as_str))
+            .chain(crates.iter().map(|(_, path)| path.as_str()))
+            .chain(codegen_backend.iter().map(String::as_str))
+    }
+}
+
 /// If the given test directive line contains an `aux-*` directive, parse it
 /// and update [`AuxProps`] accordingly.
 pub(super) fn parse_and_update_aux(config: &Config, ln: &str, aux: &mut AuxProps) {

src/tools/compiletest/src/lib.rs

@@ -862,7 +862,7 @@ fn files_related_to_test(
         related.push(testpaths.file.clone());
     }
 
-    for aux in &props.aux.builds {
+    for aux in props.aux.all_aux_path_strings() {
         // FIXME(Zalathar): Perform all `auxiliary` path resolution in one place.
         let path = testpaths.file.parent().unwrap().join("auxiliary").join(aux);
         related.push(path);