Add Mercurial fetch strategy and lwm2.

var/spack/packages/lwm2/package.py

@@ -0,0 +1,18 @@
+from spack import *
+
+class Lwm2(Package):
+    """LWM2: Light Weight Measurement Module.  This is a PMPI module
+       that can collect a number of time-sliced MPI and POSIX I/O
+       measurements from a program.
+    """
+    homepage = "https://jay.grs.rwth-aachen.de/redmine/projects/lwm2"
+
+    version('torus', hg='https://jay.grs.rwth-aachen.de/hg/lwm2', branch='torus')
+
+    depends_on("papi")
+    depends_on("mpi")
+
+    def install(self, spec, prefix):
+        configure("--prefix=%s" % prefix)
+        make()
+        make("install")