How to build LilyPond.app on macOS?

[Mojca Miklavec]

Hi,

Can someone please provide me a hint about how to build LilyPond.app
on macOS (natively, without any cross-compiling, ideally without
compiling any dependencies like ghostscript etc.)?

I checked lilypond-2.19.51.tar.gz, but it's not clear to me where the
sources for that would be. There is no obvious configure option and I
didn't find the relevant/needed files like Info.plist.

I found
    http://lilypond.org/doc/v2.18/Documentation/contributor-big-page
(didn't read it all) and only suspect that some logic might live in
GUB, but I'm pretty much lost for the moment.

I would like to see LilyPond.app being distributed in a package
manager, but for that to happen I first need to understand how to
build it.

Bonus question (I'll probably ask separately). PDF viewer shows hyperlinks to
    textedit://path/to/file.ly
How does the OS know that it has to open LilyPond.app for that as is
there a way to configure that, so that the file gets opened in another
editor? I configured the system to open my favourite text editor on
double-clicking, but it has no effect when I click on a hyperlink.

Thank you,
    Mojca

(please CC me)