Mass conversion of setup_(dependent_)?environment (#13924)

* Mass conversion of setup_(dependent_)?environment

* prefix -> self.prefix

var/spack/repos/builtin/packages/at-spi2-core/package.py

@@ -35,6 +35,6 @@ def url_for_version(self, version):
         url = 'http://ftp.gnome.org/pub/gnome/sources/at-spi2-core'
         return url + '/%s/at-spi2-core-%s.tar.xz' % (version.up_to(2), version)
 
-    def setup_environment(self, spack_env, run_env):
+    def setup_build_environment(self, env):
         # this avoids an "import site" error in the build
-        spack_env.unset('PYTHONHOME')
+        env.unset('PYTHONHOME')