Companion to getbyte but raise EOFError
Similar to https://github.com/ruby/openssl/pull/438

https://github.com/ruby/openssl/commit/c40f70711a

To be consistent with regular Ruby IOs:

```ruby
r, _ = IO.pipe
buf = "garbage".b
r.read_nonblock(10, buf, exception: false) # => :wait_readable
p buf # => "garbage"
```

Ref: https://github.com/redis-rb/redis-client/commit/98b8944460a11f8508217bda71cfc10cb2190d4d

https://github.com/ruby/openssl/commit/08452993d6

https://github.com/ruby/openssl/commit/8aa3849cff

https://github.com/ruby/openssl/commit/a3d230d4e0

Disabling ECC support of OpenSSL is impractical nowadays.

We still try to have the C extension compile on no-ec builds (as well
as no-dh or no-engine, etc.) as long as we can, but keeping test cases
for such an extreme scenario is not worth the effort.

https://github.com/ruby/openssl/commit/2cd01d4676

Import current master (2c43241dc0ed) of ruby/openssl.git.

Below are the commits that were made since the last batch at commit
b99775b163ce (ruby/openssl.git commit f49e7110ca1e). Note that some of
them have been applied already.

----------------------------------------------------------------
Benoit Daloze (1):
      Remove redundant and ignored workflow file

DBL-Lee (1):
      add support for SHA512_256/SHA512_224

Hiroshi SHIBATA (2):
      Guard for OpenSSL::PKey::EC::Group::Error with unsupported platforms
      Fixed inconsistency directory structure with ruby/ruby repo

Jeremy Evans (2):
      Fix keyword argument separation issues in OpenSSL::SSL::SSLSocket#sys{read,write}_nonblock
      Remove taint support

Kazuki Yamaguchi (26):
      config: support .include directive
      random: make OpenSSL::Random.pseudo_bytes alias of .random_bytes
      extconf.rb: get rid of -Werror=deprecated-declarations
      test/openssl/test_ssl: skip test_fallback_scsv if necessary
      ts: simplify OpenSSL::Timestamp::Request#algorithm
      History.md: add missing references to GitHub issues
      config: deprecate OpenSSL::Config#add_value and #[]=
      test/openssl/test_ssl: remove sleep from test_finished_messages
      test/openssl/test_ssl: fix random failure in SSLSocket.open test
      test/openssl/test_ssl: avoid explicitly-sized private keys
      test/openssl/test_ssl: remove commented-out test case
      test/openssl/test_ssl: allow kRSA tests to fail
      ssl: avoid declarations after statements
      engine: revert OpenSSL::Engine.load changes for cloudhsm
      engine: remove really outdated static engines
      engine: do not check for ENGINE_load_builtin_engines()
      engine: fix guards for 'dynamic' and 'cryptodev' engines
      lib/openssl.rb: require openssl/version.rb
      x509: add error code and verify flags constants
      ssl: set verify error code in the case of verify_hostname failure
      .github/workflows: merge CI jobs into a single workflow
      .github/workflows: test against different OpenSSL versions
      .travis.yml: fully migrate to GitHub Actions
      ssl: suppress test failure with SSLContext#add_certificate_chain_file
      ssl: remove test case test_puts_meta from test_pair
      Revert "Use version.rb in gemspec"

MSP-Greg (2):
      .travis.yml - remove 2.3/1.0.2, 2.5/1.1.1, head/1.0.2
      Use version.rb in gemspec

Samuel Williams (1):
      Restore compatibility with older versions of Ruby.

Yusuke Endoh (1):
      Make OpenSSL::OSSL#test_memcmp_timing robust

Import the master branch of ruby/openssl for preparing to release openssl-2.2.0

OpenSSL 1.1.1 rejects some shorter keys, which caused some failures of
`make test-all TESTS=openssl`.

https://rubyci.org/logs/rubyci.s3.amazonaws.com/debian/ruby-master/log/20190606T003005Z.fail.html.gz

This change merges 6bbc31ddd1 and 63fb3a36d1 in
https://github.com/ruby/openssl.
Reference: https://github.com/ruby/openssl/pull/217

Import Ruby/OpenSSL 2.1.0.beta2. The full commit log since commit
e72d960db262 which was imported by r60013 can be found at:

	https://github.com/ruby/openssl/compare/e72d960db262...v2.1.0.beta2

----------------------------------------------------------------
Kazuki Yamaguchi (26):
      bn: use ALLOCV() macro instead of xmalloc()
      appveyor.yml: remove 'openssl version' line
      test/test_ssl_session: skip tests for session_remove_cb
      x509ext: implement X509::Extension#==
      x509attr: implement X509::Attribute#==
      x509cert: implement X509::Certificate#==
      x509revoked: add missing X509::Revoked#to_der
      x509crl, x509revoked: implement X509::{CRL,Revoked}#==
      x509req: implement X509::Request#==
      ssl: extract rb_intern("call")
      cipher: disallow setting AAD for non-AEAD ciphers
      test/test_cipher: fix test_non_aead_cipher_set_auth_data failure
      ssl: fix conflict of options in SSLContext#set_params
      buffering: let #write accept multiple arguments
      pkey: make pkey_check_public_key() non-static
      x509cert, x509crl, x509req, ns_spki: check sanity of public key
      test/envutil: port assert_warning from Ruby trunk
      test/utils: remove a pointless .public_key call in issue_cert
      ssl: add SSLContext#add_certificate
      test/test_ssl: fix test_security_level
      Drop support for LibreSSL 2.4
      kdf: add HKDF support
      test/test_x509cert: fix flaky test
      test/test_x509crl: fix random failure
      History.md: fix a typo
      Ruby/OpenSSL 2.1.0.beta2

Mark Wright (1):
      Fix build failure against OpenSSL 1.1 built with no-deprecated Thanks rhenium for the code review and fixes.

Peter Karman (1):
      Add RSA sign_pss() and verify_pss() methods

aeris (1):
      TLS Fallback Signaling Cipher Suite Value

kazu (1):
      Use caller with length to reduce unused strings

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60907 b2dd03c8-39d4-4d8f-98ff-823fe69b080e