Merge branch 'features/cflags' into develop

Conflicts:
	lib/spack/spack/cmd/find.py
	var/spack/repos/builtin/packages/ghostscript/package.py

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

@@ -127,7 +127,7 @@ def url_for_version(self, version):
             dots, underscores)
 
     def determine_toolset(self, spec):
-        if spec.satisfies("=darwin-x86_64"):
+        if spec.satisfies("arch=darwin-x86_64"):
             return 'darwin'
 
         toolsets = {'g++': 'gcc',