configure.ac rework

- Put libusb and PC/SC check in m4 macros.
- Suppress --disable-pcsclite and --disable-libusb
- Add --with-drivers option: we now could choose which driver to build. without this option a default set is build (ATM all drivers except PN532_UART)

libnfc/drivers/pn53x_usb.c

@@ -30,6 +30,8 @@
 Thanks to d18c7db and Okko for example code
 */
 
+#if defined (DRIVER_PN531_USB_ENABLED) || defined (DRIVER_PN533_USB_ENABLED)
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <usb.h>
@@ -329,3 +331,5 @@ bool pn53x_usb_transceive(const nfc_device_spec_t nds, const byte_t* pbtTx, cons
 
   return true;
 }
+
+#endif // DRIVER_PN531_USB_ENABLED || DRIVER_PN533_USB_ENABLED