Thank you, marto. I ran prove as recommended: 
chap@Retsina:...rk/1688073614.30084/Tk-804.036$ pwd
/Users/chap/.cpanm/work/1688073614.30084/Tk-804.036
chap@Retsina:...rk/1688073614.30084/Tk-804.036$ prove -v PNG/t/basic.t
PNG/t/basic.t ..
1..5
ok 1 - use Tk::PNG;
Failed 4/5 subtests

Test Summary Report
-------------------
PNG/t/basic.t (Wstat: 11 Tests: 1 Failed: 0)
  Non-zero wait status: 11
  Parse errors: Bad plan.  You planned 5 tests but ran 1.
Files=1, Tests=1,  0 wallclock secs ( 0.03 usr  0.01 sys +  0.16 cusr 
+ 0.02 csys =  0.22 CPU)
Result: FAIL

[download]
I am by now well out of my depth, so I can't dig any further into this :-). I'm inclined not to suspect the clang compiler, since it fails in the same test for either compiler.

I did install perl-5.30.3 on M1 MacOS 13.4.1, and successfully ran cpanm Tk.

To OP: is installing a more recent version of Perl an option?

In reply to Re^4: Tk-804.036 build failure by ibm1620
in thread Tk-804.036 build failure by perlboy_emeritus

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