Since around 2018, we have been using spaces for indentation for newly
added code[1]. The mixed use of tabs and spaces has repeatedly confused
new contributors who configured their editors to use a different tab
size than 8. Since git blame can now skip specific commits, ruby/ruby
did a mass reformatting of tabs in 2022[2]. Do the same in ruby/openssl.

While at it, fix a few indentation issues, mainly in switch-case labels
and in ossl_ssl_session.c, which used doubled indentation size.

This patch contains white-space changes only. git diff -w output should
be empty.

[1] https://bugs.ruby-lang.org/issues/14246
[2] https://bugs.ruby-lang.org/issues/18891

https://github.com/ruby/openssl/commit/4d6214f507

These declarations were added to every source file because older
versions of RDoc did not resolve ancestor tree across files. Since
RDoc 6.9.0 supports this, this workaround is no longer needed.

    https://redirect.github.com/ruby/rdoc/pull/1217

https://github.com/ruby/openssl/commit/6491ce63be

ruby/openssl exposes OIDs to Ruby as strings in many places, but the
conversion logic has been duplicated and the behavior is inconsistent.
There are mainly two patterns:

 - Returns the short name associated with the OID/NID, or the dotted
   decimal notation if it is unknown to OpenSSL.
 - Returns the long name, or the dotted decimal notation.

These patterns are implemented using different OpenSSL APIs and that
caused subtle differences. Add helper functions ossl_asn1obj_to_string()
and ossl_asn1obj_to_string_long_name() to unify the logic.

Also, document the current behaviors where it is not yet done. The
inconsistency was likely unintentional, but since it dates back to the
original implementations, standardizing it now would cause more issues
than it resolves.

https://github.com/ruby/openssl/commit/2ea36c21a4

With the introduction of OpenSSL 3 providers, newly implemented
algorithms do not necessarily have a corresponding NID assigned. To use
such an algorithm, it has to be "fetched" from providers using the new
EVP_*_fetch() functions.

For digest algorithms, we have to use EVP_MD_fetch() instead of the
existing EVP_get_digestbyname(). However, it is not a drop-in
replacement because:

 - EVP_MD_fetch() does not support all algorithm name aliases recognized
   by EVP_get_digestbyname().

 - Both return an EVP_MD, but the one returned by EVP_MD_fetch() is
   sometimes reference counted and the user has to explicitly release
   it with EVP_MD_free().

So, keep using EVP_get_digestbyname() for all OpenSSL versions for now,
and fall back to EVP_MD_fetch() if it fails. In the latter case, prepare
a T_DATA object to manage the fetched EVP_MD's lifetime.

https://github.com/ruby/openssl/commit/9fc2179403

Among functions named ossl_*_new(), ossl_pkey_new() is now the only one
that takes ownership of the passed OpenSSL object instead of making a
copy or incrementing its reference counter. Rename it to make this
behavior easier to understand.

https://github.com/ruby/openssl/commit/54c1c26eb5

https://github.com/ruby/openssl/commit/17f87d2cf0

While the struct is currently still public in OpenSSL, there has been
an accessor since OpenSSL 0.9.8h. It would be nice if this accessor
could be used so that the struct can be made opaque at some point in
the future.

https://github.com/ruby/openssl/commit/812aeab2f5

https://github.com/ruby/openssl/commit/85d6b7f192

Allow requests to be signed using Ed25519 private keys by passing a nil digest.
This is similar to commit https://github.com/ruby/openssl/commit/b0fc10009120 when signing certs.

Calling PKey#public_key is deprecated and does not work for Ed25519. The same
can be accomplished by passing the private key.

https://github.com/ruby/openssl/commit/d96090320d

Update the references to the file "LICENCE" with "COPYING".

The file LICENCE doesn't exist in ruby/ruby nor ruby/openssl. This has
been always the case since OpenSSL for Ruby 2 was merged to the ruby
tree as a standard library in 2003.

In OpenSSL for Ruby 2's CVS repository[1], the LICENCE file contained
an old version of the Ruby License, identical to the COPYING file that
was in Ruby's tree at that time (r4128[2]).

[1] http://cvs.savannah.gnu.org/viewvc/rubypki/ossl2/LICENCE?revision=1.1.1.1&view=markup
[2] https://github.com/ruby/ruby/blob/231247c010acba191b78ed2d1310c935e63ad919/COPYING

https://github.com/ruby/openssl/commit/5bccf07d04