Merge pull request #447 from cstrouse/add-mercurial

Add mercurial (4.0.2) package

packages/mercurial.rb

+require 'package'
+
+class Mercurial < Package
+  version '4.0.2'
+  source_url 'https://www.mercurial-scm.org/release/mercurial-4.0.2.tar.gz'
+  source_sha1 '1d7b3eeed790974277db91bd1b0f34a5d142e980'
+
+  # what's the best route for adding a minimum version symbol as a constraint?
+  depends_on "python27"
+
+  def self.build
+    # would be great to avoid even downloading the source tarball if this dependency wasn't met 
+    py_ver = %x[python -V 2>&1 | awk '{ print $2 }'].strip
+    abort '[!] python 2.7.13 or higher is required for tig, please run `crew upgrade python27` first.' unless py_ver > '2.7.12'
+    if !%x[pip list | grep osutils].include? "osutils"
+      puts "Installing osutils dependency..."
+      system "sudo", "pip", "install", "osutils"
+    end
+    if !%x[pip list | grep docutils].include? "docutils"
+      puts "Installing docutils dependency..."
+      system "sudo", "pip", "install", "docutils"
+    end
+    system "make", "PREFIX=/usr/local", "all"
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install" 
+    puts "------------------"
+    puts "Installation success!"
+    puts "Cleaning up dependencies only required for build..."
+    system "sudo", "pip", "uninstall", "docutils"
+    puts
+    puts "To begin using mercurial you'll need to configure it."
+    puts
+    puts "Run `hg debuginstall` and address any issues that it reports."
+  end
+end