New formula: libxslt 1.1.26

Allow a keg-only libxslt because it's need by e.g. the nokogiri gem.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Formula/libxslt.rb

@@ -0,0 +1,26 @@
+require 'formula'
+
+class Libxslt < Formula
+  url 'ftp://xmlsoft.org/libxml2/libxslt-1.1.26.tar.gz'
+  homepage 'http://xmlsoft.org/XSLT/'
+  md5 'e61d0364a30146aaa3001296f853b2b9'
+
+  keg_only :provided_by_osx
+
+  depends_on 'libxml2'
+
+  def install
+    system "./configure", "--prefix=#{prefix}",
+                          "--disable-dependency-tracking",
+                          "--with-libxml-prefix=#{Formula.factory('libxml2').prefix}"
+    system "make"
+    system "make install"
+  end
+
+  def caveats; <<-EOS.undent
+    To allow the nokogiri gem to link against this libxslt, run
+
+        gem install nokogiri -- --with-xslt-dir=#{prefix}
+    EOS
+  end
+end