fix: defer volume lock to after setup, fix sighandler cast comment, check pkg-config status

crates/ahfail-display/Cargo.toml

@@ -11,7 +11,6 @@ ahfail-ui = { path = "../ahfail-ui" }
 gtk = { version = "0.15", package = "gtk", features = ["v3_24"] }
 gdk = { version = "0.15", package = "gdk", features = ["v3_24"] }
 gstreamer = { version = "0.18", package = "gstreamer", features = ["v1_18"] }
-gstreamer-player = { version = "0.18", package = "gstreamer-player" }
 glib = { version = "0.15", package = "glib" }
 libc = "0.2"
 

crates/ahfail-display/build.rs

@@ -37,6 +37,7 @@ fn main() {
         .args(["--cflags", "gio-2.0"])
         .output()
         .expect("pkg-config not found");
+    assert!(gio_cflags.status.success(), "pkg-config --cflags gio-2.0 failed");
     let gio_cflags_str = String::from_utf8(gio_cflags.stdout).unwrap();
 
     let mut build = cc::Build::new();

crates/ahfail-display/src/main.rs

@@ -14,6 +14,9 @@ extern "C" fn handle_sigterm(_: libc::c_int) {
 
 fn main() {
     unsafe {
+        // SAFETY: handle_sigterm only stores to an AtomicBool — async-signal-safe.
+        // The *const () intermediate avoids a "direct cast to integer" warning because
+        // libc::sighandler_t is size_t on Linux.
         libc::signal(libc::SIGTERM, handle_sigterm as *const () as libc::sighandler_t);
     }
 
@@ -32,17 +35,20 @@ fn main() {
         return;
     };
 
-    let volume_state = ahfail_ui::volume::save_and_set_max();
-
-    let display = gdk::Display::default().expect("[ahfail-display] No display");
-    let monitor = display
-        .primary_monitor()
-        .or_else(|| display.monitor(0))
-        .expect("[ahfail-display] No monitor");
+    let Some(display) = gdk::Display::default() else {
+        eprintln!("[ahfail-display] No display");
+        return;
+    };
+    let Some(monitor) = display.primary_monitor().or_else(|| display.monitor(0)) else {
+        eprintln!("[ahfail-display] No monitor");
+        return;
+    };
     let geom = monitor.geometry();
     let screen_w = geom.width();
     let screen_h = geom.height();
 
+    // On X11, WindowType::Popup creates an unmanaged override-redirect window (desired).
+    // On Wayland, GTK3 falls back to a normal xdg_toplevel; the compositor controls stacking.
     let window = gtk::Window::new(gtk::WindowType::Popup);
     window.set_decorated(false);
     window.set_keep_above(true);
@@ -62,6 +68,9 @@ fn main() {
 
     std::thread::spawn(|| ahfail_ui::update::check_for_update(ahfail_ui::VERSION));
 
+    // All setup succeeded — acquire volume lock now so early-exit paths above don't leave it held.
+    let volume_state = ahfail_ui::volume::save_and_set_max();
+
     glib::timeout_add_seconds(FAILSAFE_MINUTES * 60, || {
         gtk::main_quit();
         glib::Continue(false)