Spurious "file exists" exception in libcompiler_builtins build script

[alexcrichton]

Starting to see errors like:

cargo:rerun-if-changed=/checkout/src/libcompiler_builtins/../compiler-rt/cmake/Modules/CompilerRTLink.cmake
cargo:rerun-if-changed=/checkout/src/libcompiler_builtins/../compiler-rt/cmake/Modules/BuiltinTests.cmake
cargo:rerun-if-changed=/checkout/src/libcompiler_builtins/../compiler-rt/cmake/Modules/SanitizerUtils.cmake
cargo:rerun-if-changed=/checkout/src/libcompiler_builtins/../compiler-rt/cmake/config-ix.cmake
cargo:rerun-if-changed=/checkout/src/libcompiler_builtins/../compiler-rt/cmake/builtin-config-ix.cmake
cargo:rerun-if-changed=/checkout/src/libcompiler_builtins/../compiler-rt/cmake/caches/Apple.cmake
cargo:rerun-if-changed=/checkout/src/libcompiler_builtins/../compiler-rt/.arcconfig
cargo:rerun-if-changed=/checkout/src/libcompiler_builtins/../compiler-rt/Makefile
cargo:rustc-link-lib=static=compiler-rt
cargo:rustc-link-search=native=/checkout/obj/build/powerpc64le-unknown-linux-gnu/native/compiler-rt/.

--- stderr
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error { repr: Os { code: 17, message: "File exists" } }', /buildslave/rust-buildbot/slave/beta-dist-rustc-linux/build/src/libcore/result.rs:868
note: Run with `RUST_BACKTRACE=1` for a backtrace.

Build failed, waiting for other jobs to finish...
error: build failed


command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "build" "-j" "4" "--target" "powerpc64le-unknown-linux-gnu" "--release" "--locked" "--features" "panic-unwind asan lsan msan tsan jemalloc backtrace" "--manifest-path" "/checkout/src/libstd/Cargo.toml"
expected success, got: exit code: 101

I believe it's caused by a recent change (#40236) but I'm not certain, investigating now...

[alexcrichton]

cc @petrochenkov

[alexcrichton]

Ok further reflection leads me to believe this is another instance of #40337, so I'm going to close in favor of that.