As far as I can tell, BasePlugin has one method for manipulating environment variables: the env() method. I have a custom plugin where I need to be able to set certain environment variables at build-time, so I'm setting them in this method like so: ``` def env(self, root): env = super().env(root) env.extend([ 'CPPFLAGS="-std=c++11 -I{} $CPPFLAGS"'.format(os.path.join( root, 'usr', 'include')), 'CFLAGS="-std=c11 -I{} $CFLAGS"'.format(os.path.join( root, 'usr', 'include')), ]) return env ``` This works fine for building the snap, but I notice that these environment variables are then present in the command wrapper as well, so they're also being set for runtime. Most of the time this won't be a massive issue - setting CPPFLAGS has no effect at run-time, but it's a little surprising, and I can imagine situations where plugin authors will want more control over what's set at build time, and what's set at run-time.