Add mc package

Add slang dependency

packages/mc.rb

+require 'package'
+
+class Mc < Package
+  description 'GNU Midnight Commander is a visual file manager'
+  homepage 'http://midnight-commander.org/'
+  version '4.8.20'
+  source_url 'https://github.com/MidnightCommander/mc/archive/4.8.20.tar.gz'
+  source_sha256 'f6d6aebc5ab835f0593b9c30debb39bec05c8073a486aed661e09da3ebe488f9'
+
+  binary_url ({
+  })
+  binary_sha256 ({
+  })
+
+  depends_on 'automake' => :build
+  depends_on 'libtool' => :build
+  depends_on 'glib' => :build
+  depends_on 'aspell'
+  depends_on 'slang'
+
+  def self.build
+    system './autogen.sh'
+    system "./configure --prefix=#{CREW_PREFIX} --libdir=#{CREW_LIB_PREFIX}"
+    system 'make'
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install"
+  end
+end