Separated joystick state from window system state.

This is partially in preparation for pending support for additional
joystick APIs like XInput, DirectInput and IOHID.

src/linux_joystick.h

@@ -27,19 +27,33 @@
 #ifndef _linux_joystick_h_
 #define _linux_joystick_h_
 
-typedef struct _GLFWjoystickLinux {
-    struct {
-        int         present;
-        int         fd;
-        float*      axes;
-        int         axisCount;
-        unsigned char* buttons;
-        int         buttonCount;
-        char*       name;
-    } joystick[GLFW_JOYSTICK_LAST + 1];
+#define _GLFW_PLATFORM_LIBRARY_JOYSTICK_STATE \
+    _GLFWjoystickLinux joystick[GLFW_JOYSTICK_LAST + 1]
+
+
+//========================================================================
+// GLFW platform specific types
+//========================================================================
+
+//------------------------------------------------------------------------
+// Platform-specific joystick structure
+//------------------------------------------------------------------------
+typedef struct _GLFWjoystickLinux
+{
+    int             present;
+    int             fd;
+    float*          axes;
+    int             axisCount;
+    unsigned char*  buttons;
+    int             buttonCount;
+    char*           name;
 } _GLFWjoystickLinux;
 
-// Joystick input
+
+//========================================================================
+// Prototypes for platform specific internal functions
+//========================================================================
+
 void _glfwInitJoysticks(void);
 void _glfwTerminateJoysticks(void);