Add copy_dir_all function to run-make-support

Author: GuillaumeGomez

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

@@ -12,6 +12,8 @@ pub mod rustc;
 pub mod rustdoc;
 
 use std::env;
+use std::fs;
+use std::io;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Output};
 
@@ -201,6 +203,24 @@ pub fn set_host_rpath(cmd: &mut Command) {
     });
 }
 
+/// Copy a directory into another.
+pub fn copy_dir_all(src: impl AsRef<Path>, dst: impl AsRef<Path>) -> io::Result<()> {
+    let dst = dst.as_ref();
+    if !dst.is_dir() {
+        fs::create_dir_all(&dst)?;
+    }
+    for entry in fs::read_dir(src)? {
+        let entry = entry?;
+        let ty = entry.file_type()?;
+        if ty.is_dir() {
+            copy_dir_all(entry.path(), dst.join(entry.file_name()))?;
+        } else {
+            fs::copy(entry.path(), dst.join(entry.file_name()))?;
+        }
+    }
+    Ok(())
+}
+
 /// Implement common helpers for command wrappers. This assumes that the command wrapper is a struct
 /// containing a `cmd: Command` field and a `output` function. The provided helpers are:
 ///