libebml 1.3.1

Update to latest stable release, use Autotools dependency on HEAD
builds, use new configure script, modernize formula.

Formula/libebml.rb

@@ -1,12 +1,15 @@
-require 'formula'
-
 class Libebml < Formula
-  homepage 'http://www.matroska.org/'
-  url 'http://dl.matroska.org/downloads/libebml/libebml-1.3.0.tar.bz2'
-  mirror 'http://www.bunkus.org/videotools/mkvtoolnix/sources/libebml-1.3.0.tar.bz2'
-  sha256 '83b074d6b62715aa0080406ea84d33df2e44b5d874096640233a4db49b8096de'
+  homepage "http://www.matroska.org/"
+  url "http://dl.matroska.org/downloads/libebml/libebml-1.3.1.tar.bz2"
+  mirror "https://www.bunkus.org/videotools/mkvtoolnix/sources/libebml-1.3.1.tar.bz2"
+  sha256 "195894b31aaca55657c9bc157d744f23b0c25597606b97cfa5a9039c4b684295"
 
-  head 'https://github.com/Matroska-Org/libebml.git'
+  head do
+    url "https://github.com/Matroska-Org/libebml.git"
+    depends_on "automake" => :build
+    depends_on "autoconf" => :build
+    depends_on "libtool" => :build
+  end
 
   bottle do
     cellar :any
@@ -19,6 +22,11 @@ class Libebml < Formula
 
   def install
     ENV.cxx11 if build.cxx11?
-    system "make", "-C", "make/linux", "install", "prefix=#{prefix}", "CXX=#{ENV.cxx}"
+    system "autoreconf", "-fi" if build.head?
+    system "./configure", "--disable-debug",
+                          "--disable-dependency-tracking",
+                          "--disable-silent-rules",
+                          "--prefix=#{prefix}"
+    system "make", "install"
   end
 end