latexindent: trouble installing File::HomeDir, Mac::SystemDirectory since macOS 11 Big Sur

Question

Before I begin, I should note that I never had this problem on macOS 10.15 Catalina, and the responses in this similar thread did not solve the problem, unfortunately.

I'm experimenting with latexindent on a fresh install of macOS 11 Big Sur and I'm having issues with File:HomeDir: running latexindent returns a whole list of errors, beginning with Can't locate File/HomeDir.pm in @INC. I've tried using cpan to install that module, but I end up with following:

Reading '/Users/myname/.cpan/Metadata'
  Database was generated on Thu, 24 Dec 2020 05:41:03 GMT
Running install for module 'File::HomeDir'
Checksum for /Users/myname/.cpan/sources/authors/id/R/RE/REHSACK/File-HomeDir-1.006.tar.gz ok
Scanning cache /Users/myname/.cpan/build for sizes
............................................................................DONE
'YAML' not installed, will not store persistent state
Configuring R/RE/REHSACK/File-HomeDir-1.006.tar.gz with Makefile.PL
Checking if your kit is complete...
Looks good
Warning: prerequisite Mac::SystemDirectory 0.04 not found.
Generating a Unix-style Makefile
Writing Makefile for File::HomeDir
Writing MYMETA.yml and MYMETA.json
  REHSACK/File-HomeDir-1.006.tar.gz
  /usr/bin/perl Makefile.PL -- OK
Running make for R/RE/REHSACK/File-HomeDir-1.006.tar.gz
---- Unsatisfied dependencies detected during ----
----     REHSACK/File-HomeDir-1.006.tar.gz    ----
    Mac::SystemDirectory [requires]
Running install for module 'Mac::SystemDirectory'
Checksum for /Users/myname/.cpan/sources/authors/id/E/ET/ETHER/Mac-SystemDirectory-0.13.tar.gz ok
Configuring E/ET/ETHER/Mac-SystemDirectory-0.13.tar.gz with Makefile.PL
HASCOMPILERjIOx/TESTn6oE.c:2:10: fatal error: 'EXTERN.h' file not found
#include "EXTERN.h"
         ^~~~~~~~~~
1 error generated.
Couldn't execute cc  -g -pipe -fno-strict-aliasing -fstack-protector-strong -DPERL_USE_SAFE_PUTENV -Os "-I/System/Library/Perl/5.28/darwin-thread-multi-2level/CORE"   -c HASCOMPILERjIOx/TESTn6oE.c -o HASCOMPILERjIOx/TESTn6oE.o: Inappropriate ioctl for device at Makefile.PL line 14.
Requires a compiler
Warning: No success on command[/usr/bin/perl Makefile.PL]
  ETHER/Mac-SystemDirectory-0.13.tar.gz
  /usr/bin/perl Makefile.PL -- NOT OK
  REHSACK/File-HomeDir-1.006.tar.gz
  Has already been unwrapped into directory /Users/myname/.cpan/build/File-HomeDir-1.006-2
  REHSACK/File-HomeDir-1.006.tar.gz
  Has already been prepared
Running make for R/RE/REHSACK/File-HomeDir-1.006.tar.gz
Warning: Prerequisite 'Mac::SystemDirectory => 0.04' for 'REHSACK/File-HomeDir-1.006.tar.gz' failed when processing 'ETHER/Mac-SystemDirectory-0.13.tar.gz' with 'writemakefile => NO '/usr/bin/perl Makefile.PL' returned status 6400'. Continuing, but chances to succeed are limited.
cp lib/File/HomeDir/Driver.pm blib/lib/File/HomeDir/Driver.pm
cp lib/File/HomeDir/MacOS9.pm blib/lib/File/HomeDir/MacOS9.pm
cp lib/File/HomeDir/Darwin/Carbon.pm blib/lib/File/HomeDir/Darwin/Carbon.pm
cp lib/File/HomeDir/Darwin/Cocoa.pm blib/lib/File/HomeDir/Darwin/Cocoa.pm
cp lib/File/HomeDir/Windows.pm blib/lib/File/HomeDir/Windows.pm
cp lib/File/HomeDir/FreeDesktop.pm blib/lib/File/HomeDir/FreeDesktop.pm
cp lib/File/HomeDir.pm blib/lib/File/HomeDir.pm
cp lib/File/HomeDir/Test.pm blib/lib/File/HomeDir/Test.pm
cp lib/File/HomeDir/Darwin.pm blib/lib/File/HomeDir/Darwin.pm
cp lib/File/HomeDir/Unix.pm blib/lib/File/HomeDir/Unix.pm
Manifying 10 pod documents
  REHSACK/File-HomeDir-1.006.tar.gz
  /usr/bin/make -- OK
Running make test
PERL_DL_NONLAZY=1 "/usr/bin/perl" "-MExtUtils::Command::MM" "-MTest::Harness" "-e" "undef *Test::Harness::Switches; test_harness(0, 'blib/lib', 'blib/arch')" t/*.t xt/*.t
t/01_compile.t ........ 1/11 # Implemented by: File::HomeDir::Darwin
t/01_compile.t ........ ok     
t/02_main.t ........... # $<: 501 -- $(: 20 20 12 61 79 80 81 98 701 33 100 204 250 395 398 399 400
t/02_main.t ........... ok     
t/10_test.t ........... ok     
t/11_darwin.t ......... ok   
t/12_darwin_carbon.t .. skipped: Not running on 32-bit Darwin
t/13_darwin_cocoa.t ... skipped: Not running on Darwin with Cocoa API using Mac::SystemDirectory
t/20_empty_home.t ..... ok   
All tests successful.
Files=7, Tests=90,  1 wallclock secs ( 0.04 usr  0.01 sys +  0.48 cusr  0.13 csys =  0.66 CPU)
Result: PASS
  REHSACK/File-HomeDir-1.006.tar.gz
Tests succeeded but one dependency not OK (Mac::SystemDirectory)
  REHSACK/File-HomeDir-1.006.tar.gz
  [dependencies] -- NA
Failed during this command:
 ETHER/Mac-SystemDirectory-0.13.tar.gz        : writemakefile NO '/usr/bin/perl Makefile.PL' returned status 6400
 REHSACK/File-HomeDir-1.006.tar.gz            : make_test NO one dependency not OK (Mac::SystemDirectory)

I really don't know much about perl, but it seems to me that Mac::SystemDirectory is missing, When I try to install that, however, I get

Reading '/Users/myname/.cpan/Metadata'
  Database was generated on Thu, 24 Dec 2020 05:41:03 GMT
Running install for module 'Mac::SystemDirectory'
Checksum for /Users/myname/.cpan/sources/authors/id/E/ET/ETHER/Mac-SystemDirectory-0.13.tar.gz ok
Scanning cache /Users/myname/.cpan/build for sizes
............................................................................DONE
'YAML' not installed, will not store persistent state
Configuring E/ET/ETHER/Mac-SystemDirectory-0.13.tar.gz with Makefile.PL
HASCOMPILER5Emh/TESTS3W7.c:2:10: fatal error: 'EXTERN.h' file not found
#include "EXTERN.h"
         ^~~~~~~~~~
1 error generated.
Couldn't execute cc  -g -pipe -fno-strict-aliasing -fstack-protector-strong -DPERL_USE_SAFE_PUTENV -Os "-I/System/Library/Perl/5.28/darwin-thread-multi-2level/CORE"   -c HASCOMPILER5Emh/TESTS3W7.c -o HASCOMPILER5Emh/TESTS3W7.o: Inappropriate ioctl for device at Makefile.PL line 14.
Requires a compiler
Warning: No success on command[/usr/bin/perl Makefile.PL]
  ETHER/Mac-SystemDirectory-0.13.tar.gz
  /usr/bin/perl Makefile.PL -- NOT OK
Failed during this command:
 ETHER/Mac-SystemDirectory-0.13.tar.gz        : writemakefile NO '/usr/bin/perl Makefile.PL' returned status 6400

From this it seems that a header file EXTERN.h is missing, but I'm not sure where to go from here. Does anyone have any thoughts or suggestions? My apologies for the huge blocks of code - I figured it would be better to include all possible details. Thanks a lot!

Note: I posted this same question in the LaTeX Stack Exchange, but figured I would also ask here since it seems to be a broader perl issue.

Answer 1

To summarize the solution that worked for me: the issue is the header file EXTERN.h isn't on the CPATH by default in macOS 11 Big Sur. To fix this, add the directory containing EXTERN.h to CPATH:

export CPATH=/Library/Developer/CommandLineTools/SDKs/MacOSX11.1.sdk/System/Library/Perl/5.28/darwin-thread-multi-2level/CORE:$CPATH

Then open the cpan shell (just type cpan then enter into the command line) and type install Mac::SystemDirectory. After this process finished I was able to install File:HomeDir as well, and some other modules, to get latexindent working.

Note: I had to set up cpan before I did this; just opening the shell and following the instructions was sufficient.

Thanks a lot to Håkon Hægland for the solution!