* Windows: Fix warning about undefined if_indextoname()

* Windows: Fix UNIXSocket on MINGW and make .pair more reliable

* Windows: Use nonblock=true for read tests with scheduler

* Windows: Move socket detection from File.socket? to File.stat

Add S_IFSOCK to Windows and interpret reparse points accordingly.
Enable tests that work now.

* Windows: Use wide-char functions to UNIXSocket

This fixes behaviour with non-ASCII characters.
It also fixes deletion of temporary UNIXSocket.pair files.

* Windows: Add UNIXSocket tests for specifics of Windows impl.

* Windows: fix VC build due to missing _snwprintf

Avoid usage of _snwprintf, since it fails linking ruby.dll like so:

  linking shared-library x64-vcruntime140-ruby320.dll
  x64-vcruntime140-ruby320.def : error LNK2001: unresolved external symbol snwprintf
  x64-vcruntime140-ruby320.def : error LNK2001: unresolved external symbol vsnwprintf_l

whereas linking miniruby.exe succeeds.

This patch uses snprintf on the UTF-8 string instead.

Also remove branch GetWindowsDirectoryW, since it doesn't work.

* Windows: Fix dangling symlink test failures

Co-authored-by: Lars Kanis <kanis@comcard.de>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52576 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* test/socket/test_nonblock.rb: increase buffer sizes to
  OpenBSD limits.  Thanks to Jeremy Evans <code@jeremyevans.net>
  [ruby-core:70058]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51310 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

OpenBSD's limit is less than 128.

* test/socket/test_nonblock: use smaller buffer for sendmsg
  Patch-by: Jeremy Evans <code@jeremyevans.net>
  [ruby-core:70016] [Bug #11364]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51288 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* time: Object#timeout has been deprecated a long time ago, use
  Timeout.timeout.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51225 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* test/socket/test_nonblock.rb (test_recv_nonblock_no_exception),
  (test_recvfrom_nonblock_no_exception): use assert_predicate for
  failure messages.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50917 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* test/socket/test_nonblock.rb (test_recvfrom_nonblock_no_exception):
  no destination to already connected socket.  fix failure on OSX.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50916 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

This reduces GC overhead and makes the API more consistent
with IO#read and IO#read_nonblock.

* ext/socket/basicsocket.c (bsock_recv): document outbuf
* ext/socket/unixsocket.c (unix_recvfrom): ditto
* ext/socket/init.c (rsock_strbuf, recvfrom_locktmp): new functions
  (rsock_s_recvfrom): support destination buffer as 3rd arg
  (rsock_s_recvfrom_nonblock): ditto
* string.c (rb_str_locktmp_ensure): export for internal ext
* test/socket/test_nonblock.rb: test recv_nonblock
* test/socket/test_unix.rb: test recv
  [ruby-core:69543] [Feature #11242]

Benchmark results:

             user     system      total        real
alloc    0.130000   0.280000   0.410000 (  0.420656)
extbuf   0.100000   0.220000   0.320000 (  0.318708)

-------------------8<--------------------
require 'socket'
require 'benchmark'
nr = 100000
msg = ' ' * 16384
size = msg.bytesize
buf = ' ' * size
UNIXSocket.pair(:DGRAM) do |a, b|
  Benchmark.bmbm do |x|
    x.report('alloc') do
      nr.times do
        b.send(msg, 0)
        a.recv(size, 0)
      end
    end

    x.report('extbuf') do
      nr.times do
        b.send(msg, 0)
        a.recv(size, 0, buf)
      end
    end
  end
end

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50912 b2dd03c8-39d4-4d8f-98ff-823fe69b080e