Otherwise internal dependencies have auto-generated names that are not
human readable. Instead, use the name that the dependency overrides. For
example:
```meson
meson.override_dependency('zlib', declare_dependency())
dep_zlib = dependency('zlib')
assert(dep_zlib.name() == 'zlib')
```
Fixes: #12967
This removes the warning when using default_options without fallback
kwarg completely because a subproject does not know if the main project
has an implicit fallback or not, so it could set default_options even if
not fallback is available at all.
Fixes: #9278
It should build the fallback subprject with default_library=static and
override the dependency for both static=True and static kwarg not given.
Fixes: #8050.