Non-unique package declarations produce incomprehensible error message

[kflynn]

Given a.q:

quark 0.7.6;

package a_package 1.0.0;

use ./b.q;

namespace a_namespace { }

and b.q:

quark 0.7.6;

package a_package 1.0.0;

namespace a_namespace { }

you'll get the following incomprehensible error message when you try to compile a.q:

$ quark compile --python a.q
Checking environment ... done.
Parsing: a.q .....
Compiling quark code ...

reflector:2:5: duplicate definition of Root (first definition reflector:2:5)

If you give b.q a unique package name, all is well.

(An actual use case which doesn't involve empty namespaces is discovery.q, which needs to include discovery_utils.q, which adds some stuff into the discovery namespace.)