* 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.

* See https://github.com/oracle/truffleruby/issues/1818

Add definition for mruby 2.1.0

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

Update to OpenSSL 1.1.1d for Ruby 2.5+

Closes #1232

Don’t look for Homebrew openssl

Closes #1353 closes #1360

Fix #1311

https://travis-ci.org/rbenv/ruby-build/builds/607144159

Ref. #1234

Closes #1234

This is for simplicity and usability in scripts.

Fixes #1170

Hopefully this works between BSD and GNU mktemp.

Closes #540

Ref. #1135

Ref. #1372, fix #1373, fix #1246

Add definition for jruby 9 2 9 0

Remove overzealous permission change post-install

Allows group-writeable Ruby installations

Reverts e1b50e68

Fix #400, close #903

Turn on `--enable-shared` by default for all supported MRI Rubies

Some gems need the host ruby to have shared library enabled. Currently,
we're not aware of any potential downsides to having this enabled by
default.

> Shared libraries are libraries that are loaded by programs when they
> start. When a shared library is installed properly, all programs that
> start afterwards automatically use the new shared library.
> [...] if you have a program that needs a shared library (in this case ruby
> libruby.so.2.2.0 or similar) the program will fail if it doesn't exist.