Fix libsql-ffi build on Windows (#2005)

libsql-ffi build on Windows has been intermittently broken for a while
due _build.rs_ calling `cp` which is not present on Windows.

Timeline:
- 2024-08-10: Issue #1657 was opened.
- 2024-11-14: #1791 was merged. First fix using `#[cfg(windows)]`.
- 2024-11-15: #1791 reverted in 9499c3c for breaking libsql-js on macOS.
- 2024-12-04: 9499c3c was reverted since #1791 was fine and did not
cause the macOS problem. Windows build works again.
- 2025-03-17: da54c1b breaks Windows build.
- 2025-03-21: 0.9.1 is released with broken Windows build.
- 2025-03-27: This commit fixes the bug introduced in da54c1b.

This commit fixes a bug introduced by da54c1b. `Command::status()?` was
propogating the error so the fallback, `fs::copy`, was never reached.
This is now fixed so libsql-ffi builds again on Windows.

Closes #1657

Author: avinassh

libsql-ffi/build.rs

@@ -76,22 +76,20 @@ fn copy_dir_all(src: impl AsRef<Path>, dst: impl AsRef<Path>) -> io::Result<()>
 /// propagate into OUT_DIR. If not present, when trying to rewrite a file, a `Permission denied`
 /// error will occur.
 fn copy_with_cp(from: impl AsRef<Path>, to: impl AsRef<Path>) -> io::Result<()> {
-    let status = Command::new("cp")
+    match Command::new("cp")
         .arg("--no-preserve=mode,ownership")
         .arg("-R")
         .arg(from.as_ref().to_str().unwrap())
         .arg(to.as_ref().to_str().unwrap())
-        .status()?;
-
-    if status.success() {
-        return Ok(());
+        .status()
+    {
+        Ok(status) if status.success() => Ok(()),
+        _ => match fs::copy(from.as_ref(), to.as_ref()) {
+            Err(err) if err.kind() == io::ErrorKind::InvalidInput => copy_dir_all(from, to),
+            Ok(_) => Ok(()),
+            Err(err) => Err(err),
+        },
     }
-
-    return match fs::copy(from.as_ref(), to.as_ref()) {
-        Err(err) if err.kind() == io::ErrorKind::InvalidInput => copy_dir_all(from, to),
-        Ok(_) => Ok(()),
-        Err(err) => Err(err),
-    };
 }
 
 fn make_amalgamation() {