What's going on? Seems like `area_for` doesn't like `mmap`.

```cpp
#include <sys/mman.h>
#include <OS.h>

int main()
{
	void* mem = mmap((void*)0x191b5690000, 0x7eff0000, PROT_NONE, MAP_ANON | MAP_PRIVATE, -1, 0);
	area_for(mem);
}
```


```
[ 10811] map_file("test mmap area", [0x191b5690000], B_BASE_ADDRESS, 0x7eff0000, 0, 0x1, true, 0xffffffff, 0x0) = 0x9085d ([0x191b5690000]) (740 us)
[ 10811] area_for(0x191b5690000) = 0xffffffff (79 us)
[ 10811] exit_team(0x0) (349 us)

```