use the nightly compiler on windows to build platforms

crates/compiler/build/src/link.rs

@@ -633,6 +633,12 @@ pub fn rebuild_host(
         );
 
         let mut cargo_cmd = cargo();
+
+        if cfg!(windows) {
+            // on windows, we need the `+nightly` toolchain so we can use `-Z export-executable-symbols`
+            cargo_cmd.arg("+nightly");
+        }
+
         cargo_cmd.arg("build").current_dir(cargo_dir);
         // Rust doesn't expose size without editing the cargo.toml. Instead just use release.
         if matches!(opt_level, OptLevel::Optimize | OptLevel::Size) {

crates/utils/src/lib.rs

@@ -126,7 +126,14 @@ pub fn get_lib_path() -> Option<PathBuf> {
 /// Gives a friendly error if cargo is not installed.
 /// Also makes it easy to track where we use cargo in the codebase.
 pub fn cargo() -> Command {
-    let command_str = "cargo";
+    let command_str = if cfg!(windows) {
+        // on windows, we need the version of cargo installed by rustup. The meaning of `cargo` is
+        // different within a process that runs rust. So we need to explicitly refer to where
+        // rustup put the binary
+        r"%HOMEPATH%\.cargo\bin\cargo.exe"
+    } else {
+        "cargo"
+    };
 
     if check_command_available(command_str) {
         Command::new(command_str)