Don't build SDL_JOYSTICK_HIDAPI by default on iOS

If you enable this, you'll need to link with CoreBluetooth.framework and add something like this to your Info.plist:
<key>NSBluetoothPeripheralUsageDescription</key>
<string>MyApp would like to remain connected to nearby bluetooth Game Controllers and Game Pads even when you're not using the app.</string>

src/hidapi/ios/hid.m

@@ -3,6 +3,9 @@
 // Purpose: HID device abstraction temporary stub
 //
 //=============================================================================
+#include "../../SDL_internal.h"
+
+#ifdef SDL_JOYSTICK_HIDAPI
 
 #include <CoreBluetooth/CoreBluetooth.h>
 #include <QuartzCore/QuartzCore.h>
@@ -907,3 +910,5 @@ int HID_API_EXPORT hid_read_timeout(hid_device *dev, unsigned char *data, size_t
 #endif
 	return result;
 }
+
+#endif /* SDL_JOYSTICK_HIDAPI */

src/hidapi/libusb/hid.c

@@ -22,6 +22,9 @@
  code repository located at:
         http://github.com/signal11/hidapi .
 ********************************************************/
+#include "../../SDL_internal.h"
+
+#ifdef SDL_JOYSTICK_HIDAPI
 
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE /* needed for wcsdup() before glibc 2.10 */
@@ -1613,3 +1616,5 @@ uint16_t get_usb_code_for_current_locale(void)
 #ifdef NAMESPACE
 }
 #endif
+
+#endif /* SDL_JOYSTICK_HIDAPI */

src/hidapi/linux/hid.c

@@ -20,6 +20,9 @@
  code repository located at:
         http://github.com/signal11/hidapi .
 ********************************************************/
+#include "../../SDL_internal.h"
+
+#ifdef SDL_JOYSTICK_HIDAPI
 
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE /* needed for wcsdup() before glibc 2.10 */
@@ -891,3 +894,5 @@ HID_API_EXPORT const wchar_t * HID_API_CALL  hid_error(hid_device *dev)
 #ifdef NAMESPACE
 }
 #endif
+
+#endif /* SDL_JOYSTICK_HIDAPI */

src/hidapi/mac/hid.c

@@ -19,6 +19,9 @@
  code repository located at:
  http://github.com/signal11/hidapi .
  ********************************************************/
+#include "../../SDL_internal.h"
+
+#ifdef SDL_JOYSTICK_HIDAPI
 
 /* See Apple Technical Note TN2187 for details on IOHidManager. */
 
@@ -1184,3 +1187,5 @@ int main(void)
 	return 0;
 }
 #endif
+
+#endif /* SDL_JOYSTICK_HIDAPI */

src/hidapi/windows/hid.c

@@ -19,6 +19,9 @@
  code repository located at:
         http://github.com/signal11/hidapi .
 ********************************************************/
+#include "../../SDL_internal.h"
+
+#ifdef SDL_JOYSTICK_HIDAPI
 
 #include <windows.h>
 
@@ -39,7 +42,6 @@ typedef LONG NTSTATUS;
 #endif
 
 /* SDL C runtime functions */
-#include "../../SDL_internal.h"
 #include "SDL_stdinc.h"
 
 #define calloc SDL_calloc
@@ -982,3 +984,5 @@ int __cdecl main(int argc, char* argv[])
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
+
+#endif /* SDL_JOYSTICK_HIDAPI */