The fix of PR eclipse-tycho#2978 was a partial fix for issue eclipse-tycho#2977. It fixed the case
of a single bundled but when the bundle providing/requiring the virtual
IU is required by another bundle it fails with the same error as before
even with Tycho 4.0.4:

```
[ERROR] Cannot resolve project dependencies:
[ERROR]   Software being installed: pvumb.bundle2 1.0.0.qualifier
[ERROR]   Missing requirement: pvumb.bundle1 1.0.0.qualifier requires 'org.eclipse.equinox.p2.iu; configure.pvumb.bundle1 0.0.0' but it could not be found
[ERROR]   Cannot satisfy dependency: pvumb.bundle2 1.0.0.qualifier depends on: osgi.bundle; pvumb.bundle1 0.0.0
```

A workaround is to use:

```
requires.0.optional=true
requires.0.greedy=true
```