BOOST_NO_CTYPE_FUNCTIONS and BSD OS's

While looking at include/boost/config/platform/bsd.hpp and updating the OpenBSD bits I noticed this
bit of the header.

```
//
// The BSD has macros only, no functions:
//
#if !defined(__OpenBSD__) || defined(__DragonFly__)
# define BOOST_NO_CTYPE_FUNCTIONS
#endif
```

I was wondering if this needed any further changes for the current state, but looking at each respective
ctype.h header for the BSD's I am not sure if this should be set or not. Could someone who is familiar
with this area comment after taking a look at the headers? I have provided URLs below,

https://gitweb.dragonflybsd.org/dragonfly.git/blob_plain/HEAD:/include/ctype.h
https://raw.githubusercontent.com/freebsd/freebsd-src/main/include/ctype.h
http://cvsweb.netbsd.org/bsdweb.cgi/~checkout~/src/include/ctype.h?rev=1.35&only_with_tag=MAIN
http://cvsweb.openbsd.org/cgi-bin/cvsweb/~checkout~/src/include/ctype.h?rev=1.25

Start with include/boost/config/platform/bsd.hpp and inspect the linked DragonFly BSD, FreeBSD, NetBSD, and OpenBSD ctype.h headers. Determine which BSD platforms provide ctype functions rather than only macros, then update the platform condition if needed; done means BOOST_NO_CTYPE_FUNCTIONS accurately reflects each listed OS.

Written by the indexing model from the issue text.