support .lz archives

Closes Homebrew/homebrew#24775.

Library/Homebrew/dependency_collector.rb

@@ -178,6 +178,7 @@ class DependencyCollector
   def parse_url_spec(url, tags)
     case File.extname(url)
     when '.xz'  then Dependency.new('xz', tags)
+    when '.lz'  then Dependency.new('lzip', tags)
     when '.rar' then Dependency.new('unrar', tags)
     when '.7z'  then Dependency.new('p7zip', tags)
     end

Library/Homebrew/download_strategy.rb

@@ -162,6 +162,9 @@ class CurlDownloadStrategy < AbstractDownloadStrategy
     when :xz
       with_system_path { safe_system "#{xzpath} -dc \"#{tarball_path}\" | tar xf -" }
       chdir
+    when :lzip
+      with_system_path { safe_system "#{lzippath} -dc \"#{tarball_path}\" | tar xf -" }
+      chdir
     when :pkg
       safe_system '/usr/sbin/pkgutil', '--expand', tarball_path, basename_without_params
       chdir
@@ -185,6 +188,10 @@ class CurlDownloadStrategy < AbstractDownloadStrategy
     "#{HOMEBREW_PREFIX}/opt/xz/bin/xz"
   end
 
+  def lzippath
+    "#{HOMEBREW_PREFIX}/opt/lzip/bin/lzip"
+  end
+
   def chdir
     entries = Dir['*']
     case entries.length

Library/Homebrew/extend/pathname.rb

@@ -141,7 +141,7 @@ class Pathname
   def extname(path=to_s)
     BOTTLE_EXTNAME_RX.match(path)
     return $1 if $1
-    /(\.(tar|cpio|pax)\.(gz|bz2|xz|Z))$/.match(path)
+    /(\.(tar|cpio|pax)\.(gz|bz2|lz|xz|Z))$/.match(path)
     return $1 if $1
     return File.extname(path)
   end
@@ -207,6 +207,7 @@ class Pathname
     when /^\037\235/n           then :compress
     when /^.{257}ustar/n        then :tar
     when /^\xFD7zXZ\x00/n       then :xz
+    when /^LZIP/n               then :lzip
     when /^Rar!/n               then :rar
     when /^7z\xBC\xAF\x27\x1C/n then :p7zip
     else