Add support for `sockaddr_un` on Windows. (#6513)

* 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>

1 files changed, 2 insertions, 1 deletions

diff --git a/file.c b/file.c
index 3e772bd099..10eb1081e3 100644
--- a/file.c
+++ b/file.c
@@ -1765,8 +1765,8 @@ rb_file_socket_p(VALUE obj, VALUE fname)
 
     if (rb_stat(fname, &st) < 0) return Qfalse;
     if (S_ISSOCK(st.st_mode)) return Qtrue;
-
 #endif
+
     return Qfalse;
 }
 
@@ -5600,6 +5600,7 @@ rb_stat_init(VALUE obj, VALUE fname)
     if (STAT(StringValueCStr(fname), &st) == -1) {
         rb_sys_fail_path(fname);
     }
+
     if (DATA_PTR(obj)) {
         xfree(DATA_PTR(obj));
         DATA_PTR(obj) = NULL;