Log Message:
Update lang/erlang to 19.0 (R19)

- compiler, stdlib:
  - New preprocessor macros ?FUNCTION_NAME, ?FUNCTION_ARITY
  - New preprocessor directives -error(Term) and -warning(Term) to
    cause a compilation error or warning, respectively.
- gen_statem a new state machine behavior
- mnesia_ext: plugin of external storage solutions to mnesia
- crypto: uses EVP interface in OpenSSL resulting in generally
  better performance and support for HW acceleration
- ssh: performance improvements, uses the new gen_statem behavior
- ssl: enhanced error log messages
- dialyzer: the support for maps is very much extended both the
  type specification syntax and the type analysis.
- erts:
  - erlang:open_port(spawn, ...) 3-5 times faster
  - tracing, extensive improvements (scalability, speed, match
    specifications on send/receive, support for lttng, ...)
  - dirty schedulers improved
  - per process configurable handling of message_queue
  - fast loading of multiple modules
  - max_heap_size process flag
- erts/kernel: Experimental support for Unix Domain Sockets

Full changelog:

  http://erlang.org/download/otp_src_19.0.readme