comment #2:

> Thanks Khalid. Can you explain how your commit solves the problem (where the configure script would "... start downloading the tarballs of the ones that are missing and build and install them.").
>

Submitted the patch as an starting point to solve it. But yeah it was unnecessary.

> In this commit, you have only toggled the printing of optional depedencies (which are printed at the end anyway), you are not downloading tarballs and building the necessary programs from source (as the task suggests)

I shall try dealing with the actual issue now.

Thanks Khalid. Can you explain how your commit solves the problem (where the configure script would "... start downloading the tarballs of the ones that are missing and build and install them.").

In this commit, you have only toggled the printing of optional depedencies (which are printed at the end anyway), you are not downloading tarballs and building the necessary programs from source (as the task suggests)

The procedure to download, unpack and install Gnuastro's dependencies from source is very standard and well known (as described in the manual).

So to greatly simplify the necessary steps a new Gnuastro user has to take, we can add a configure-time option like `--enable-build-dependencies'.

When this option is called, once the configure script checks all the dependencies, it can start downloading the tarballs of the ones that are missing and build and install them. Afterwards it can re-do the checks to make sure they are installed and usable and continue with its other checks.

This will greatly simplify the installation process for new users, while also ensuring that they get the latest packages.

All Gnuastro's dependencies are very small and basic libraries (except for Ghostscript!). For Ghostscript we can use the user's package manager, or just ignore it over all (it is only for generating PDF outputs in ConvertType), its not an mandatory, or even important, dependency.

In fact, with the various package manager commands we have gathered in the book for the dependencies, we might also be able to simply use them (instead of downloading and building them from source).

Probably we can implement this simpler solution first, or build from source only when the operating system's package manager is not recognized.