Stop using the non-standard basename_r() function.

[ed]

Summary

This change makes the code use the POSIX basename() function. It has the
advantage that (if implemented correctly), it also imposes no restrict
on the pathname length.

Notice that I haven't added any error handling to the strdup() call. It
looks like none of the other calls to strdup() and malloc() performed by
this utility do it either.

[hrs]

Looks good to me. Do we need strdup(), BTW? I think FreeBSD's basename() does not change
memory area where name points though SUS says it may be changed.

[ed]

In D6626#140418, @hrs wrote:

Looks good to me. Do we need strdup(), BTW? I think FreeBSD's basename() does not change
memory area where name points though SUS says it may be changed.

My plan is to switch over to the POSIX prototype in 12.0-CURRENT. ;-)

[hrs]

In D6626#140434, @ed wrote:

In D6626#140418, @hrs wrote:

Looks good to me. Do we need strdup(), BTW? I think FreeBSD's basename() does not change
memory area where name points though SUS says it may be changed.

My plan is to switch over to the POSIX prototype in 12.0-CURRENT. ;-)

Ah, I see. So please go ahead with your original patch.