This doesn't actually AND value with S_IFMT as claimed in the commit message: it masks out S_IFMT.
I'd also like some explanation of why we're doing this.  Saying "as per POSIX 2001" isn't much help, as (a) I don't have a copy of that spec to hand and (b) I suspect it's quite a large document and most of it isn't actually relevant to this change.  So what is S_IFMT and why do we want to mask it out ?

Also, the line of code could be simplified by use of the &= operator:
```
value &= ~S_IFMT; /* Mask out file-type; leave just the permissions */
```