add end-to-end test

tests/run-make/rust-lld/Makefile

@@ -0,0 +1,8 @@
+include ../tools.mk
+
+# ignore-msvc
+# needs-rust-lld
+# ignore-s390x lld does not yet support s390x as target
+all:
+	RUSTC_LOG=rustc_codegen_ssa::back::link=info $(RUSTC) -Clink-self-contained=+linker -Clinker-flavor=gnu-lld-cc -Zunstable-options -Clink-args=-Wl,-v main.rs 2> $(TMPDIR)/output.txt
+	$(CGREP) -e "^LLD [0-9]+\.[0-9]+\.[0-9]+" < $(TMPDIR)/output.txt

tests/run-make/rust-lld/main.rs

@@ -0,0 +1,4 @@
+// Test linking using `cc` with `rust-lld`, using the unstable CLI described in MCP 510
+// see https://github.com/rust-lang/compiler-team/issues/510 for more info
+
+fn main() {}