Merge branch 'develop' into mplegendre-multi_pkgsrc_roots

Conflicts:
	lib/spack/spack/cmd/create.py
	lib/spack/spack/cmd/extensions.py
	lib/spack/spack/cmd/fetch.py
	lib/spack/spack/cmd/uninstall.py
	lib/spack/spack/config.py
	lib/spack/spack/database.py
	lib/spack/spack/directory_layout.py
	lib/spack/spack/packages.py
	lib/spack/spack/spec.py

var/spack/repos/builtin/packages/jemalloc/package.py

@@ -0,0 +1,24 @@
+from spack import *
+
+class Jemalloc(Package):
+    """jemalloc is a general purpose malloc(3) implementation that emphasizes fragmentation avoidance and scalable concurrency support."""
+    homepage = "http://www.canonware.com/jemalloc/"
+    url      = "https://github.com/jemalloc/jemalloc/releases/download/4.0.4/jemalloc-4.0.4.tar.bz2"
+
+    version('4.0.4', '687c5cc53b9a7ab711ccd680351ff988')
+
+    variant('stats', default=False, description='Enable heap statistics')
+    variant('prof', default=False, description='Enable heap profiling')
+
+    def install(self, spec, prefix):
+        configure_args = ['--prefix=%s' % prefix,]
+
+        if '+stats' in spec:
+            configure_args.append('--enable-stats')
+        if '+prof' in spec:
+            configure_args.append('--enable-prof')
+
+        configure(*configure_args)
+
+        make()
+        make("install")