But that's the most recent commit message
<UPDATE>
I just tried running
cpan -i Tk on 64-bit SP-5.32.1 and that built and installed Tk-804.036 just fine.
I think the key to that success is that 5.32.1 uses gcc-8.3.0, whereas 5.38.2 uses gcc-13.1.0.
Downgrading to SP-5.32.1 would therefore seem to be another option for the OP.
</UPDATE>
Also, near the top of the page to which you linked, I see "5 months ago by Slaven Rezic".
And there's no mention of perl version and archname, or of gcc-version, which could be relevant.
The Tk source that I tried was from
the github repo as of last week.
Still ... if you can tell me from where I can obtain this source that you are referencing, I'll give it a go.
Cheers,
Rob