After running for quite some time, some interp in my program has executed 2147000000. As the interp doesn't seem to be misbehaving, I would like to increase its command limit by another 1000000. That results in an error: "command limit value must be at least 0"
This happened on Tcl 8.6.14, so I thought to test in the latest 9.0 as that changed "everything" to 64 bits. But to my dismay I could still easily reproduce the error:
```
% [interp create] limit commands -value 2148000000
command limit value must be at least 0```

The manual page for Tcl_LimitSetCommands() does indicate that commandLimit is of type Tcl_Size. But the reverse function, Tcl_LimitGetCommands() is still documented to return an int.

Diving into the source code, I see that Tcl_LimitGetCommands() actually returns a Tcl_Size, as I would have expected. However, I also find that ChildCommandLimitCmd() calls Tcl_LimitSetCommands() with variable `limit`, which is still an int!