Add libxslt, cleanup libxml2.

var/spack/packages/libxml2/package.py

@@ -9,6 +9,9 @@ class Libxml2(Package):
 
     version('2.9.2', '9e6a9aca9d155737868b3dc5fd82f788')
 
+    depends_on('zlib')
+    depends_on('xz')
+
     def install(self, spec, prefix):
         configure("--prefix=%s" % prefix,
                   "--without-python")

var/spack/packages/libxslt/package.py

+from spack import *
+
+class Libxslt(Package):
+    """Libxslt is the XSLT C library developed for the GNOME
+       project. XSLT itself is a an XML language to define
+       transformation for XML. Libxslt is based on libxml2 the XML C
+       library developed for the GNOME project. It also implements
+       most of the EXSLT set of processor-portable extensions
+       functions and some of Saxon's evaluate and expressions
+       extensions."""
+    homepage = "http://www.xmlsoft.org/XSLT/index.html"
+    url      = "http://xmlsoft.org/sources/libxslt-1.1.28.tar.gz"
+
+    version('1.1.28', '9667bf6f9310b957254fdcf6596600b7')
+
+    depends_on("libxml2")
+    depends_on("xz")
+    depends_on("zlib")
+    depends_on("libgcrypt")
+
+    def install(self, spec, prefix):
+        configure("--prefix=%s" % prefix)
+        make()
+        make("install")