Don't use get_plugins() in mu-plugin loader

[danielbachhuber]

Doing so requires include_once( ABSPATH . 'wp-admin/includes/plugin.php' );, which breaks things on installation.

The better approach is to just use some variant of glob()

[joehoyle]

Hmm good point, I wanted the native plugin header searching etc rather than a glob, maybe we can work around that

[joehoyle]

After discussing with @danielbachhuber , I think the best thing to do is put require_once ... for each plugin in plugins-mu. plugins-mu is used for programmatically loading anyway, so we don't really have a need for "automatic loading" more than just the convenience.