Fix build issues on Linux.

hid-libusb.c

@@ -38,6 +38,9 @@ static struct libusb_transfer *transfer;    // async transfer descriptor
 static unsigned char receive_buf[42];       // receive buffer
 static volatile int nbytes_received = 0;    // receive result
 
+#define HID_INTERFACE   0                   // interface index
+#define TIMEOUT_MSEC    500                 // receive timeout
+
 //
 // Callback function for asynchronous receive.
 // Needs to fill the receive_buf and set nbytes_received.

rd5r.c

@@ -272,7 +272,6 @@ typedef struct {
 
 //
 // General settings.
-// TODO: verify the general settings with official CPS
 //
 typedef struct {
     // Bytes e0-e7
@@ -283,8 +282,7 @@ typedef struct {
 } general_settings_t;
 
 //
-// General settings.
-// TODO: verify the general settings with official CPS
+// Intro messages.
 //
 typedef struct {
     // Bytes 7540-754f