Cannot build Perl libgd on Mac Perlbrew environment - perl

Question

I was using Mac OS 12 and Perlbrew with Perl 5.36.
When I install GD using either CPAN or cpanm I get the following error:
cpanm (App::cpanminus) 1.7046 on perl 5.036000 built for darwin-2level
Work directory is /Users/mjb/.cpanm/work/1673722431.48328
You have make /usr/bin/make
You have LWP 6.67
You have /usr/bin/tar: bsdtar 3.5.1 - libarchive 3.5.1 zlib/1.2.11 liblzma/5.0.5 bz2lib/1.0.8
You have /usr/bin/unzip
Searching install () on cpanmetadb ...
install is up to date. (0.01)
Searching GD () on cpanmetadb ...
--> Working on GD
Fetching http://www.cpan.org/authors/id/R/RU/RURBAN/GD-2.76.tar.gz
-> OK
Unpacking GD-2.76.tar.gz
Entering GD-2.76
Checking configure dependencies from META.json
Checking if you have ExtUtils::Constant 0.22 ... Yes (0.25)
Checking if you have ExtUtils::PkgConfig 0 ... Yes (1.16)
Configuring GD-2.76
Running Makefile.PL
Notice: Type perl Makefile.PL -h for command-line option summary.
Package gdlib was not found in the pkg-config search path.
Perhaps you should add the directory containing `gdlib.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gdlib' found
at Makefile.PL line 530.
*** can not find package gdlib
*** check that it is properly installed and available in PKG_CONFIG_PATH
at Makefile.PL line 530.
-> N/A
-> FAIL Configure failed for GD-2.76. See /Users/mjb/.cpanm/work/1673722431.48328/build.log for details.
The above is the contents of build.log. I'm not sure how to investigate further or fix it.
Previously I had Perl's GD install and build using the system Perl. I also have libgd installed from Homebrew and I included /usr/local/lib in the env var PKG_CONFIG_PATH. Still no avail.
Would appreciate help as I rely upon GD for my personal projects. Thanks.

Answer 1

Found it... something (probably me botching my .zshrc) had unset my $PKG_CONFIG_PATH!
After finding out what pkg-config was and scouring my drive for any telling collection of .pc files, I found gdlib.pc under /usr/local/lib/pkgconfig/gdlib.pc.
Then I simply did an export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig/ and reran the installation. Perl's GD built and installed without grumbling.
A pernanment solution will be to add the above line to your ~/.zshrc.