Store a "removable" flag instead of the full drive type in the server
file object; this way we don't need to use GetDriveTypeW in the loader
code.
Make sure we always have a valid builtin_load_info pointer.

diff --git a/server/file.h b/server/file.h
index 8bc09e9..890cdb3 100644
--- a/server/file.h
+++ b/server/file.h
@@ -91,7 +91,7 @@
                                   unsigned int access );
 extern int get_file_unix_fd( struct file *file );
 extern int is_same_file( struct file *file1, struct file *file2 );
-extern int get_file_drive_type( struct file *file );
+extern int is_file_removable( struct file *file );
 extern int grow_file( struct file *file, int size_high, int size_low );
 extern struct file *create_temp_file( int access );
 extern void file_set_error(void);