What the Script Does

Downloads and Extracts Dependencies:

   The script downloads the required libraries (GTK, Cairo, Pango, GLib, and GDKPixbuf) from their respective URLs and extracts them.
Builds Dependencies: It changes into the extracted directory, runs the ./configure script, then runs make and sudo make install to install the dependencies.
Builds and Installs GIMP: After the dependencies are installed, the script downloads and extracts the GIMP source code, then builds and installs GIMP.

Notes:

Dependencies:

Ensure you have the necessary tools installed for building the dependencies, such as make, gcc, autoconf, etc. If they are missing, you will need to install them manually.
Permissions: The script uses sudo for installing dependencies and GIMP, so you'll need to enter your password for the make install step.
Time: The process may take a while because it involves downloading and compiling multiple dependencies. Make sure your macOS system is connected to the internet and has sufficient resources for the build.

Disclaimer:

This approach does not require any package managers like Homebrew or MacPorts and automates the entire process, simplifying the task of building GIMP from source on macOS.