renaming behavior creates broken code

Example

foo.glsl

struct Foo {
  ...
};

uint doFoo(in Foo foo) { ... }

bar.glsl

#pragma glslify: doFoo = require('./foo.glsl')

The resulting code for bar.glsl when run through glslify is

struct Foo_0 {
  ...
};

uint doFoo_0(in Foo foo) { ... }

struct Foo_0 {
  ...
};

uint doFoo_0(in Foo_0 foo) { ... }

The generated code is broken due to renaming only the exported struct and not uses within the same file.