diff --git a/src/ftdi.c b/src/ftdi.c
index ff26166..756c10b 100644
--- a/src/ftdi.c
+++ b/src/ftdi.c
@@ -1018,8 +1018,8 @@ static int ftdi_to_clkbits_AM(int baudrate, unsigned long *encoded_divisor)
     static const char am_adjust_up[8] = {0, 0, 0, 1, 0, 3, 2, 1};
     static const char am_adjust_dn[8] = {0, 0, 0, 1, 0, 1, 2, 3};
     int divisor, best_divisor, best_baud, best_baud_diff;
-    divisor = 24000000 / baudrate;
     int i;
+    divisor = 24000000 / baudrate;
 
     // Round down to supported fraction (AM only)
     divisor -= am_adjust_dn[divisor & 7];
@@ -1393,7 +1393,7 @@ int ftdi_write_data(struct ftdi_context *ftdi, const unsigned char *buf, int siz
     return offset;
 }
 
-static void ftdi_read_data_cb(struct libusb_transfer *transfer)
+static void LIBUSB_CALL ftdi_read_data_cb(struct libusb_transfer *transfer)
 {
     struct ftdi_transfer_control *tc = (struct ftdi_transfer_control *) transfer->user_data;
     struct ftdi_context *ftdi = tc->ftdi;
@@ -1475,7 +1475,7 @@ static void ftdi_read_data_cb(struct libusb_transfer *transfer)
 }
 
 
-static void ftdi_write_data_cb(struct libusb_transfer *transfer)
+static void LIBUSB_CALL ftdi_write_data_cb(struct libusb_transfer *transfer)
 {
     struct ftdi_transfer_control *tc = (struct ftdi_transfer_control *) transfer->user_data;
     struct ftdi_context *ftdi = tc->ftdi;
diff --git a/src/ftdi_stream.c b/src/ftdi_stream.c
index 2180672..d295a02 100644
--- a/src/ftdi_stream.c
+++ b/src/ftdi_stream.c
@@ -61,7 +61,7 @@ typedef struct
  *
  * state->result is only set when some error happens
  */
-static void
+static void LIBUSB_CALL
 ftdi_readstream_cb(struct libusb_transfer *transfer)
 {
     FTDIStreamState *state = transfer->user_data;