add LinuxInput for Gamepad support

Source/Engine/Platform/Linux/LinuxInput.h

@@ -0,0 +1,39 @@
+#if PLATFORM_LINUX
+
+#include <string>
+#include "/usr/include/linux/input-event-codes.h"
+#include "/usr/include/linux/input.h"
+#include "Engine/Input/Input.h"
+#include "Engine/Input/Gamepad.h"
+
+using namespace std;
+
+#define LINUXINPUT_MAX_GAMEPADS 8
+#define LINUXINPUT_MAX_GAMEPAD_EVENTS_PER_FRAME 32
+#define TRIGGER_THRESHOLD 1000
+
+class LinuxGamepad : public Gamepad
+{
+    struct State {
+        bool Buttons[32];
+        float Axis[32];
+    };
+    public:
+    LinuxGamepad(u_int32_t uid[], string name);
+    ~LinuxGamepad();
+    int fd;
+    string dev;
+    State _state;
+    bool UpdateState();
+};
+
+class LinuxInput
+{
+    public:
+    static void UpdateState();
+    static void DetectGamePads();
+    static void DumpDevices();
+    static void Init();
+};
+
+#endif