C wishlist: __attribute__((noreturn))

Seen under Infer 0.2.0 on Ubuntu 14.10 x86_64.

I'm working with code that has its own error handling (e.g. implements its own assert()), and I see a fair number of cases where something like 'assert(p != NULL)' doesn't stop Infer from complaining about a later dereference of p. E.g.:

```
#include

extern void error_path() __attribute__((noreturn));

void f(void)
{
int *p = malloc(sizeof *p);

if (!p)
error_path();

/* This is reported as a NULL_DEREFERENCE,
* although we can't reach here with p == NULL. */
p[0] = 1;

free(p);
}
```

It would be nice to have this Just Work[tm]. :)