transform_mjit_header.rb: no extra CRs

* tool/transform_mjit_header.rb (MJITHeader.check_code!): open
  temporary file in binary mode too, not to include extra CRs.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62222 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/transform_mjit_header.rb

@@ -77,7 +77,7 @@ module MJITHeader
   # Return true if CC with CFLAGS compiles successfully the current code.
   # Use STAGE in the message in case of a compilation failure
   def self.check_code!(code, cc, cflags, stage)
-    Tempfile.open(['', '.c']) do |f|
+    Tempfile.open(['', '.c'], mode: File::BINARY) do |f|
       f.puts code
       f.close
       unless system("#{cc} #{cflags} #{f.path}", err: File::NULL)