Using latest GNU Make in formula build section

[lelegard]

Hi,

In the next version of a formula (tsduck), GNU Make version 4+ will be required. Up to the current version of the formula, the version 3.81 of the GNU Make which is installed with macOS was sufficient. This is no longer true.

Now, when building the formula, we need the "make" which comes with Homebrew (version 4.4.1 as of today). However, that make is installed as gmake on macOS. On Linux, we don't need it.

Being ignorant in Ruby, I need some advice on the best way to update the formula so that:

1. depends_on "make" => :build is used on macOS only
2. In the install section, the various system "make" ... commands become system "gmake" on macOS only.

In the past, I have seen that some potentially complicated things were elegantly solved by Homebrew maintainers in one single obscure line (obscure to me). I am curious to see how to solve this one the right way.

[carlocab]

You could do

on_macos do
  depends_on "make" => :build
end

and then in the install method you should be able to call gmake unconditionally since that will still resolve to the right executable on Linux.

I'm also tempted to say that we should make the make dependency unconditional for simplicity, but I'll leave that up to you.