attempt to test RUSTC and RUSTC_WRAPPER shenanigans on CI

Author: RalfJung

ci.sh

@@ -38,8 +38,21 @@ function run_tests {
   else
     PYTHON=python
   fi
+  # Some environment setup that attempts to confuse the heck out of cargo-miri.
+  if [ "$HOST_TARGET" = x86_64-unknown-linux-gnu ];
+    # These act up on Windows (`which miri` produces a filename that does not exist?!?),
+    # so let's do this only on Linux. Also makes sure things work without these set.
+    export RUSTC=$(which rustc)
+    export MIRI=$(which miri)
+  fi
+  mkdir -p .cargo
+  echo 'build.rustc-wrapper = "thisdoesnotexist"' > .cargo/config.toml
+  # Run the actual test
   ${PYTHON} test-cargo-miri/run-test.py
   echo
+  # Clean up
+  unset RUSTC MIRI
+  rm -rf .cargo
 
   # Ensure that our benchmarks all work, on the host at least.
   if [ -z "${MIRI_TEST_TARGET+exists}" ]; then