Drop “static inline”

* The C++11 standard (N3337) states in section 3.2 (One definition rule)
  paragraph 5 that non-static function templates may be defined in more
  than one translation unit; dropping the “static” therefore allows us
  to reuse those template instantiations between translation units
  (implemented as weak symbols in practice). If the “static” is dropped,
  “inline” makes no sense, either, so drop it, too.