Add stick and trigger input support

backends/include/pd_system/hid_glfw.hpp

@@ -3,6 +3,7 @@
 #include <pd/drivers/hid.hpp>
 
 typedef struct GLFWwindow GLFWwindow;
+typedef struct GLFWgamepadstate GLFWgamepadstate;
 
 namespace PD {
 class HidGlfw : public HidDriver {
@@ -13,6 +14,7 @@ class HidGlfw : public HidDriver {
   void Update() override;
 
  private:
+  void HandleAxisKey(GLFWgamepadstate s, int iK, int eA, bool negative);
   struct Impl;
   Impl* impl;
 };