BSE: cxxaux.hh: add PersistentStaticInstance<> to work around static ctors
BSE: cxxaux.hh: add PersistentStaticInstance<> to work around static ctors

Avoid the "C++ Static Initialization Order Fiasco" by wrapping your static
instances into a `static PersistentStaticInstance<CustomeClass>` template.
This constructs `CustomeClass` on demand, without using the heap and never
triggers its destructor.

Signed-off-by: Tim Janik <6ec6ff229c4e1c5bbd5933ee92e6c5832ff023bb@gnu.org>

swesterfeld/beast,tim-janik/beast,tim-janik/beast,tim-janik/beast,tim-janik/beast,tim-janik/beast,swesterfeld/beast,tim-janik/beast,swesterfeld/beast,tim-janik/beast,swesterfeld/beast,swesterfeld/beast,swesterfeld/beast,swesterfeld/beast