ruby-build 20191124
* Update to OpenSSL 1.1.1d for Ruby 2.5+
Closes #1232
* Set default MAKE=gmake on FreeBSD again
as an workaround for Ruby bug 16331: https://bugs.ruby-lang.org/issues/16331
Due to this bug, build will fail with FreeBSD's make after #1368.
The bug is already fixed in MRI upstream but GNU make is still required
when building older releases of Ruby. Use GNU make rather than switching
make/gmake depending of Ruby version.
See also: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=241633
* Add TruffleRuby 19.3.0
* Add definition for mruby 2.1.0
* Use the full path to the post-install hook to help debugging issues
* See https://github.com/oracle/truffleruby/issues/1818
* Use openssl from Homebrew for TruffleRuby on macOS
* The openssl built by ruby-build was not used by TruffleRuby,
and causes https://github.com/oracle/truffleruby/issues/1818
* Improve error message when openssl from Homebrew is not available.
* Change the definition code so it checks the operating system too.