sineweave example drops into ldb on SBCL/ubuntu/x86_64
The sineweave example starts but dies after a second or so with the following error if I run it from SLIME. If I run it from the SBCL command prompt directly, everything works.

```
free(): invalid pointer
fatal error encountered in SBCL pid 19874(tid 0x7f16ba2af700):
SIGABRT received.

Error opening /dev/tty: No such device or address
Welcome to LDB, a low-level debugger for the Lisp runtime environment.
ldb> backtrace
Backtrace:
   0: Foreign function gsignal, pc = 0x7f16e018fed7, fp = 0x7f16ba2ae5f0
ldb> 
```