Add check for package compatibility

packages/xkeyboard_config.rb

@@ -4,6 +4,7 @@ require 'package'
 class Xkeyboard_config < Package
   description 'The non-arch keyboard configuration database for X Window.'
   homepage 'http://www.freedesktop.org/wiki/Software/XKeyboardConfig'
+  compatibility 'all'
   version '2.29'
   source_url 'https://www.x.org/releases/individual/data/xkeyboard-config/xkeyboard-config-2.29.tar.bz2'
   source_sha256 '1d4175278bf06000683656763a8b1d3282c61a314b6db41260c8efe92d621802'
@@ -23,8 +24,11 @@ class Xkeyboard_config < Package
 
   depends_on 'libx11'
 
-  def self.build
+  def self.patch
     system "sed -i 's,/usr/bin/python3,#{CREW_PREFIX}/bin/python3,' ./rules/compat/map-variants.py"
+  end
+
+  def self.build
     system "./configure --prefix=#{CREW_PREFIX} --libdir=#{CREW_LIB_PREFIX}"
     system 'make'
   end
@@ -32,5 +36,4 @@ class Xkeyboard_config < Package
   def self.install
     system 'make', "DESTDIR=#{CREW_DEST_DIR}", 'install'
   end
-
 end