Can't get ngx-bootstrap to work in plugin

[kcsampson]

Using the Angular 8 cli branch.

I'm trying to get anything from ngx-bootstrap to simply work in a plugin, even if the plugin imports the entire library.

I was able to get @angular/material working just fine.

Placing an entry linke 'ngx-bootstrap' in externals doesn't do the trick. I get:

ERROR Error: Uncaught (in promise): NullInjectorError: StaticInjectorError(AppModule)[t -> function(){}]:
StaticInjectorError(Platform: core)[t -> function(){}]:
NullInjectorError: No provider for function(){}!
NullInjectorError: StaticInjectorError(AppModule)[t -> function(){}]:
StaticInjectorError(Platform: core)[t -> function(){}]:
NullInjectorError: No provider for function(){}!
at NullInjector.push../node_modules/@angular/core/fesm5/core.js.NullInjector.get