Ensure functions return a value

otherwise, gcc errored out
because non-void functions are supposed to return a value.

Alternatively, we could change the declaration to `void`.

scsiapi/scsiapi_windows.c

@@ -235,6 +235,7 @@ int scsi_write(struct scsi_device * dev, const unsigned char * data, size_t data
     | Free the buffer                                       |
     \*-----------------------------------------------------*/
     free(buffer);
+    return 0;
 }
 #ifdef __cplusplus
 }