Writing of crash dumps were done using unbuffered IO. This
is slow since many small writes are done.

Use a FILE* with an allocated buffer to obtain buffered IO.

I wrote a small test program that created 50000 binaries of 200 bytes
each and then created a crash dump. The crash dumping was an order of
magnitude faster with buffered IO than without.

OTP-14331

* rickard/pcre-8.40:
  Update documentation
  Update README.pcre_update.md
  Stack guard for PCRE
  Adjust for incompatibility between PCRE 8.40 and perl 5.22.1
  Generate re replacement and split tests with perl vsn 5.22.1
  Fix re_SUITE:pcre_compile_workspace_overflow/1
  Skip line with lockout of modifiers in PCRE tests
  Update tests for PCRE version 8.40
  Update PCRE to version 8.40

Conflicts:
	erts/emulator/beam/beam_debug.c

Improve accuracy of timeouts using a premature timeout then
return to sleep with a shorter timeout just before requested
timeout. This approach is only used on certain platforms where
we know it improves the accuracy of the timeouts, e.g. MacOS X.

* henrik/update-copyrightyear:
  update copyright-year