diff --git a/var/spack/packages/clang/package.py b/var/spack/packages/clang/package.py
index 4f10385dbda396225986154f27b7944ddc3f1d86..4f977bf9a440fd69bdc599748649d1bd657f44dd 100644
--- a/var/spack/packages/clang/package.py
+++ b/var/spack/packages/clang/package.py
@@ -28,11 +28,16 @@ class Clang(Package):
     """The goal of the Clang project is to create a new C, C++,
        Objective C and Objective C++ front-end for the LLVM compiler.
     """
-    homepage = "http://clang.llvm.org"
-    list_url = "http://llvm.org/releases/download.html"
+    homepage = 'http://clang.llvm.org'
+    url = 'http://llvm.org/releases/3.7.0/cfe-3.7.0.src.tar.xz'
 
-    depends_on("llvm")
-    version('3.4.2', '87945973b7c73038871c5f849a818588', url='http://llvm.org/releases/3.4.2/cfe-3.4.2.src.tar.xz')
+    depends_on('llvm@3.7.0', when='@3.7.0')
+    depends_on('llvm@3.6.2', when='@3.6.2')
+    depends_on('llvm@3.5.1', when='@3.5.1')
+
+    version('3.7.0', '8f9d27335e7331cf0a4711e952f21f01', url='http://llvm.org/releases/3.7.0/cfe-3.7.0.src.tar.xz')
+    version('3.6.2', 'ff862793682f714bb7862325b9c06e20', url='http://llvm.org/releases/3.6.2/cfe-3.6.2.src.tar.xz')
+    version('3.5.1', '93f9532f8f7e6f1d8e5c1116907051cb', url='http://llvm.org/releases/3.5.1/cfe-3.5.1.src.tar.xz')
 
     def install(self, spec, prefix):
         env['CXXFLAGS'] = self.compiler.cxx11_flag
diff --git a/var/spack/packages/llvm/package.py b/var/spack/packages/llvm/package.py
index a1939aadacc254db6d5fd54e030444dd28fe94d9..a6759c3033ed5d96aba3b8001913faf805cfaa59 100644
--- a/var/spack/packages/llvm/package.py
+++ b/var/spack/packages/llvm/package.py
@@ -39,15 +39,15 @@ class Llvm(Package):
     version('3.6.2', '0c1ee3597d75280dee603bae9cbf5cc2', url='http://llvm.org/releases/3.6.2/llvm-3.6.2.src.tar.xz')
     version('3.5.1', '2d3d8004f38852aa679e5945b8ce0b14', url='http://llvm.org/releases/3.5.1/llvm-3.5.1.src.tar.xz')
 
+    depends_on('python@2.7:')
+
     def install(self, spec, prefix):
         env['CXXFLAGS'] = self.compiler.cxx11_flag
 
         with working_dir('spack-build', create=True):
             cmake('..',
                   '-DLLVM_REQUIRES_RTTI=1',
-                  '-DPYTHON_EXECUTABLE=/usr/bin/python',
-                  '-DPYTHON_INCLUDE_DIR=/usr/include/python2.6',
-                  '-DPYTHON_LIBRARY=/usr/lib64/libpython2.6.so',
+                  '-DPYTHON_EXECUTABLE=%s/bin/python' % spec['python'].prefix,
                   *std_cmake_args)
             make()
             make("install")