build: Use temporary file for can_compile (#1497)

The can_compile function in build.rs previously invoked rustc with
-o -, which causes rustc to attempt to create a temporary metadata
directory in the current working directory.

When building with Portage for ChromeOS, this happens in a sandbox where
the current working directory is not writeable, resulting in a sandbox
access violation.

This change modifies the can_compile function to use a temporary
directory for the output file. This forces rustc to create the temporary
file in a writeable location, avoiding the sandbox issue.

Author: keiichiw

build.rs

@@ -258,7 +258,7 @@ fn can_compile<T: AsRef<str>>(test: T) -> bool {
         .arg("--target")
         .arg(target)
         .arg("-o")
-        .arg("-")
+        .arg(std::env::temp_dir().join("rustix_test_can_compile"))
         .stdout(Stdio::null()); // We don't care about the output (only whether it builds or not)
 
     // If Cargo wants to set RUSTFLAGS, use that.