Welcome to NetBSD signals

Summary:
Signals 1-32 are matching the default UNIX platform.

There are platform specific ones above 32.

From the `/usr/include/sys/signal.h` header:

```
#define SIGPWR          32      /* power fail/restart (not reset when caught) */
#ifdef _KERNEL
#define SIGRTMIN        33      /* Kernel only; not exposed to userland yet */
#define SIGRTMAX        63      /* Kernel only; not exposed to userland yet */
#endif
```

Reviewers: emaste, joerg

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D15482

llvm-svn: 255592