Cannot find perl.h when installing Tk on macOS Catalina 10.15.5

[hakonhagland]

I am trying to install Tk using the system perl (version 5.18.4) on macOS Catalina 10.15.5:

$ perl Makefile.PL
Cannot find '/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE/perl.h' have you installed perl?
Compilation failed in require at Makefile.PL line 37.
BEGIN failed--compilation aborted at Makefile.PL line 39.

[hakonhagland]

I believe this is because Apple removed the Perl system headers from archlibexp in macOS 10.14, see this issue for more information. I get the following:

$ perl -MConfig -E'say $Config{archlibexp}'
/System/Library/Perl/5.18/darwin-thread-multi-2level 
$ ls /System/Library/Perl/5.18/darwin-thread-multi-2level/CORE
libperl.dylib

So there is no perl.h there, but on the other hand Apple has moved the header to this place:

$ ls /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE
EXTERN.h             dosish.h             handy.h              malloc_ctl.h         op_reg_common.h      perldtrace.h         proto.h              time64.h             warnings.h
INTERN.h             embed.h              hv.h                 metaconfig.h         opcode.h             perlio.h             reentr.h             time64_config.h
XSUB.h               embedvar.h           hv_func.h            mg.h                 opnames.h            perliol.h            regcharclass.h       uconfig.h
av.h                 fakesdio.h           inline.h             mg_data.h            overload.h           perlsdio.h           regcomp.h            unicode_constants.h
bitcount.h           fakethr.h            intrpvar.h           mg_raw.h             pad.h                perlsfio.h           regexp.h             unixish.h
charclass_invlists.h feature.h            iperlsys.h           mg_vtable.h          parser.h             perlvars.h           regnodes.h           utf8.h
config.h             form.h               keywords.h           mydtrace.h           patchlevel.h         perly.h              scope.h              utfebcdic.h
cop.h                git_version.h        l1_char_class_tab.h  nostdio.h            perl.h               pp.h                 sv.h                 util.h
cv.h                 gv.h                 libperl.tbd          op.h                 perlapi.h            pp_proto.h           thread.h             uudmap.h

See also this question on stackoverflow.com

[levigutt]

can this be solved in any way? how would I tell the installer to look in the right place for the header-file?

[PeterisP]

Stumbled into this same issue, mac OS 15.3.1 on ARM, couldn't find any workaround anywhere.