Add package dependencies as suggested by @jam7

packages/libass.rb

@@ -5,6 +5,8 @@ class Libass < Package
   source_url 'https://github.com/libass/libass/archive/0.13.6.tar.gz'
   source_sha1 '10fc35f8aba2a4a37aaed482a4184d144defb3d8'
 
+  depends_on 'automake'
+  depends_on 'autoconf'
   depends_on 'freetype'
   depends_on 'fribidi'
   depends_on 'fontconfig'

packages/libfdkaac.rb

@@ -5,6 +5,8 @@ class Libfdkaac < Package
   source_url 'https://github.com/mstorsjo/fdk-aac/archive/v0.1.5.tar.gz'
   source_sha1 '2894bd6d21066bfdf65a2f8cb6d2ca2dde597194'
 
+  depends_on 'automake'
+
   def self.build
     system "./autogen.sh"
     system "./configure"

packages/libfrei0r.rb

@@ -6,6 +6,7 @@ class Libfrei0r < Package
   source_sha1 'a8214add5828e20ff49239ed3a462acaa8c1ebb2'
 
   depends_on 'cmake'
+
   def self.build
     system "cmake ."
     system "make"