Rewrite linux global hotkey to not depend on any libraries (also allows it to work on non-systemd systems(?)), remove unused gsr-window-name

tools/gsr-global-hotkeys/hotplug.h

@@ -0,0 +1,22 @@
+#ifndef HOTPLUG_H
+#define HOTPLUG_H
+
+/* C stdlib */
+#include <stdbool.h>
+
+typedef struct {
+    int fd;
+    bool event_is_add;
+    bool subsystem_is_input;
+    char event_data[1024];
+} hotplug_event;
+
+typedef void (*hotplug_device_added_callback)(const char *devname, void *userdata);
+
+bool hotplug_event_init(hotplug_event *self);
+void hotplug_event_deinit(hotplug_event *self);
+
+int hotplug_event_steal_fd(hotplug_event *self);
+void hotplug_event_process_event_data(hotplug_event *self, int fd, hotplug_device_added_callback callback, void *userdata);
+
+#endif /* HOTPLUG_H */