From ae0fd2ab79b0e46d3bd9fc89170d8db99bb91489 Mon Sep 17 00:00:00 2001
From: Lars Kanis <lars@greiz-reinsdorf.de>
Date: Tue, 15 Jun 2021 15:13:39 +0200
Subject: [PATCH 1/3] Fix Windows libc detection for MSYS2-ucrt build

Take the same approach for detection as used in fiddle:
  https://github.com/ruby/ruby/blob/79717f81f8ba24960cca6c934d00c72db64139ed/test/fiddle/helper.rb#L55-L56
---
 lib/ffi/platform.rb | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/lib/ffi/platform.rb b/lib/ffi/platform.rb
index 0f0639e48..bf01a27ad 100644
--- a/lib/ffi/platform.rb
+++ b/lib/ffi/platform.rb
@@ -132,11 +132,8 @@ def self.is_os(os)
     end
 
     LIBC = if IS_WINDOWS
-      if RbConfig::CONFIG['host_os'] =~ /mingw/i
-        RbConfig::CONFIG['RUBY_SO_NAME'].split('-')[-2] + '.dll'
-      else
-        "ucrtbase.dll"
-      end
+      crtname = RbConfig::CONFIG["RUBY_SO_NAME"][/msvc\w+/] || 'ucrtbase'
+      "#{crtname}.dll"
     elsif IS_GNU
       GNU_LIBC
     elsif OS == 'cygwin'

From 3dd973eb384804e9448e483db973d06c0548d1bf Mon Sep 17 00:00:00 2001
From: Lars Kanis <lars@greiz-reinsdorf.de>
Date: Tue, 15 Jun 2021 15:28:05 +0200
Subject: [PATCH 2/3] Use _time on Windows UCRT platform

---
 bench/bench_time.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bench/bench_time.rb b/bench/bench_time.rb
index aaec64f36..8454f811b 100644
--- a/bench/bench_time.rb
+++ b/bench/bench_time.rb
@@ -4,7 +4,7 @@ module BenchTime
   module Posix
     extend FFI::Library
     ffi_lib FFI::Library::LIBC
-    if RUBY_PLATFORM =~ /mswin/
+    if RUBY_PLATFORM =~ /mswin/ || FFI::Library::LIBC =~ /ucrt/
       attach_function :time, :_time64, [ :buffer_out ], :uint64, ignore_error: true
     else
       attach_function :time, [ :buffer_out ], :ulong, ignore_error: true

From 3a5bef5c1ad4f3ebfcdbb89b3564c981b1ae24c8 Mon Sep 17 00:00:00 2001
From: Lars Kanis <lars@greiz-reinsdorf.de>
Date: Tue, 15 Jun 2021 15:49:56 +0200
Subject: [PATCH 3/3] Better test

---
 bench/bench_time.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bench/bench_time.rb b/bench/bench_time.rb
index 8454f811b..099ec3086 100644
--- a/bench/bench_time.rb
+++ b/bench/bench_time.rb
@@ -4,7 +4,7 @@ module BenchTime
   module Posix
     extend FFI::Library
     ffi_lib FFI::Library::LIBC
-    if RUBY_PLATFORM =~ /mswin/ || FFI::Library::LIBC =~ /ucrt/
+    if FFI::Library::LIBC =~ /ucrtbase/
       attach_function :time, :_time64, [ :buffer_out ], :uint64, ignore_error: true
     else
       attach_function :time, [ :buffer_out ], :ulong, ignore_error: true