Building from source without homebrew or any other package manager.
Download the latest version of the [https://pkg-config.freedesktop.org/releases/?C=M;O=A](pkg-config source).
LDFLAGS="-framework CoreFoundation -framework Carbon" ./configure --with-internal-glib
make
sudo make install
Thank you very much. To compile another binary pkg-config was a requirement although I'll never use it. You're the first one to explain how to compile the damn thing on macOS in plain human language. Additionally, the official GitLab link given on freedesktop.org to download "the source code" landed me with a package without the configure exec but with vastly inarticulate instructions.