configure is checking for `ttyname` but code is using `ttyname_r`

[glebm]

Bug report

Bug description:

PR #14868 by @chibby0ne changed the code to use ttyname_r but the configure script is checking for ttyname.

There are some old systems, such as OSX Tiger, that don't have ttyname_r (at least not by default), so it'd be nice if ttyname_r was checked for separately with fallback to ttyname.

CPython versions tested on:

3.11, 3.12

Operating systems tested on:

macOS

Linked PRs

• gh-127614: Correctly check for ttyname_r() in configure #128503
• [3.13] gh-127614: Correctly check for ttyname_r() in configure (#128503) #128598
• [3.12] gh-127614: Correctly check for ttyname_r() in configure (#128503) #128599

[erlend-aasland]

Mac OS X Tiger is not supported; I'm not sure it is worth it to add a fallback to ttyname. I agree, though, that we should fix the build dependency check.