spotlights-macbook-air: Initialize muvm

hosts/linux/spotlights-macbook-air/muvm/run-passthru.patch

@@ -0,0 +1,32 @@
+diff --git a/crates/muvm/src/guest/mount.rs b/crates/muvm/src/guest/mount.rs
+index 02c507d..232299b 100644
+--- a/crates/muvm/src/guest/mount.rs
++++ b/crates/muvm/src/guest/mount.rs
+@@ -14,6 +14,13 @@ use rustix::mount::{
+ use rustix::path::Arg;
+ use serde_json::json;
+ 
++/// A list of directories in /run to be passed through from the host.
++const RUN_PASSTHRU: [&str; 2] = [
++    // NixOS-specific directories.
++    "current-system",
++    "opengl-driver",
++];
++
+ fn make_tmpfs(dir: &str) -> Result<()> {
+     mount2(
+         Some("tmpfs"),
+@@ -313,6 +320,13 @@ pub fn mount_filesystems(merged_rootfs: bool) -> Result<()> {
+     )
+     .context("Failed to mount `/dev/shm`")?;
+ 
++    for dir in RUN_PASSTHRU {
++        let src = Path::new("/run/muvm-host/run").join(dir);
++        if src.exists() {
++            symlink(src, Path::new("/run").join(dir))?;
++        }
++    }
++
+     // Do this last so it can pick up all the submounts made above.
+     if let Err(e) = mount_fex_rootfs(merged_rootfs) {
+         println!("Failed to mount FEX rootfs, carrying on without. Error: {e}");