Create xorg_requirement.rb

[rwhogg]

This creates a new XorgRequirement class and hacks X11Requirement to defer to it as necessary.
It also removes some hackery from xquartz.rb that just pretended X11 was already installed.

Closes #951

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[rwhogg]

I cannot emphasize enough how much a work-in-progress this is. It works, but telling the various X11Requirement methods to defer to their XorgRequirement counterparts is just awful.

What I think might work better is having XorgRequirement extend X11Requirement and mapping depends_on :x11 to

Nevertheless, submitting the PR so there's a visible indication of my progress.

[rwhogg]

I've just removed this for now, but I think I need to do more than that.

Assuming we want to prefer the Linuxbrew/xorg/xorg installation over anything else, something like this might make more sense (pardon my mediocre Ruby-fu):

if OS.linux?
  @prefix ||= if Pathname.new(cellar/"xorg").exist?
    # Not sure if this case is really necessary... not all that familiar with this code ATM
    Pathname.new(ENV["HOMEBREW_PREFIX"])
  elsif Pathname.new("/usr/lib/x86_64-linux-gnu/libX11.so").exist?
    Pathname.new("/usr")
  end
end

[tseemann]

On RHEL/Centos that libX11.so doesn't exist - it is in /usr/lib64/libX11.so

[sjackman]

LinuxbrewTestBot error:

  1) Error:
X11RequirementTests#test_satisfied:
TapFormulaUnavailableError: No available formula with the name "linuxbrew/xorg/xorg" 
Please tap it and then try again: brew tap linuxbrew/xorg

I thought that this bug was fixed. =/
See #938 and Homebrew/legacy-homebrew#50271

[sjackman]

What I think might work better is having XorgRequirement extend X11Requirement and mapping depends_on :x11 to XorgRequirement

👍

[sjackman]

$ brew install gobject-introspection
==> Tapping homebrew/dupes
Cloning into '/home/sjackman/.linuxbrew/Library/Taps/homebrew/homebrew-dupes'...

It looks fixed to me. I wonder why this requirement doesn't tap. Perhaps because it's in brew tests which behaves differently than reality some times…
Does the auto-tapping work when you try it outside of brew tests?

[rwhogg]

Moved to Linuxbrew/brew#10