Don't write to /dev/null on mingw. [#3921 state:resolved] (ht: Patrick Daryll Glandien)

activesupport/lib/active_support/core_ext/kernel/reporting.rb

@@ -37,7 +37,7 @@ def silence_stderr #:nodoc:
   #   puts 'But this will'
   def silence_stream(stream)
     old_stream = stream.dup
-    stream.reopen(RUBY_PLATFORM =~ /mswin/ ? 'NUL:' : '/dev/null')
+    stream.reopen(RUBY_PLATFORM =~ /mswin|mingw/ ? 'NUL:' : '/dev/null')
     stream.sync = true
     yield
   ensure