Add RecursiveMutex class and fix deadlock in remove_listener

include/gamepad/event_handler.hpp

@@ -7,6 +7,7 @@
 #include <atomic>
 
 #include "gamepad/todo.hpp"
+#include "gamepad/recursive_mutex.hpp"
 #include "pros/rtos.hpp"
 
 namespace Gamepad {
@@ -52,6 +53,6 @@ template <typename... Args> class EventHandler {
         }
     private:
         std::map<uint32_t, Listener> listeners;
-        pros::Mutex mutex;
+        Gamepad::RecursiveMutex mutex;
 };
 } // namespace Gamepad

include/gamepad/recursive_mutex.hpp

@@ -0,0 +1,29 @@
+#include "pros/apix.h"
+#include "pros/rtos.h"
+#include <system_error>
+
+namespace Gamepad {
+
+class RecursiveMutex {
+    public:
+    RecursiveMutex(): mutex(pros::c::mutex_recursive_create()) {}
+    bool take(std::uint32_t timeout = TIMEOUT_MAX) {
+        return pros::c::mutex_recursive_take(mutex, timeout);
+    }
+    void lock() {
+        if (!this->take()) throw std::system_error();
+    }
+    bool try_lock() {
+        return this->take(0);
+    }
+    bool give() {
+        return pros::c::mutex_recursive_give(mutex);
+    }
+    void unlock() {
+        this->give();
+    }
+    private:
+    pros::mutex_t mutex;
+};
+
+}