Remove all usages of tmp_dir from tests

src/tools/run-make-support/src/cc.rs

@@ -1,9 +1,7 @@
 use std::path::Path;
 use std::process::Command;
 
-use crate::{
-    bin_name, cygpath_windows, env_var, handle_failed_output, is_msvc, is_windows, tmp_dir, uname,
-};
+use crate::{bin_name, cygpath_windows, env_var, handle_failed_output, is_msvc, is_windows, uname};
 
 /// Construct a new platform-specific C compiler invocation.
 ///

src/tools/run-make-support/src/clang.rs

@@ -1,7 +1,7 @@
 use std::path::Path;
 use std::process::Command;
 
-use crate::{bin_name, env_var, handle_failed_output, tmp_dir};
+use crate::{bin_name, env_var, handle_failed_output};
 
 /// Construct a new `clang` invocation. `clang` is not always available for all targets.
 pub fn clang() -> Clang {

src/tools/run-make-support/src/lib.rs

@@ -171,6 +171,11 @@ pub fn bin_name(name: &str) -> String {
     if is_windows() { format!("{name}.exe") } else { name.to_string() }
 }
 
+/// Return the current working directory.
+pub fn cwd() -> PathBuf {
+    env::current_dir().unwrap()
+}
+
 /// Use `cygpath -w` on a path to get a Windows path string back. This assumes that `cygpath` is
 /// available on the platform!
 #[track_caller]