[Truffle] Some IO constants.

spec/truffle/tags/rubysl/rubysl-stringio/spec/open_tags.txt

@@ -1,6 +1 @@
-fails:StringIO.open when passed [Object, mode] allows passing the mode as an Integer
 fails:StringIO.open when passed [Object, mode] raises a TypeError when passed a frozen String in truncate mode as StringIO backend
-fails:StringIO.open when passed [Object, mode] raises a RuntimeError when passed a frozen String in truncate mode as StringIO backend
-fails:StringIO.open when passed no arguments yields self to the passed block
-fails:StringIO.open when passed no arguments sets the mode to read-write
-fails:StringIO.open when passed no arguments uses an empty String as the StringIO backend

spec/truffle/tags/rubysl/rubysl-stringio/spec/reopen_tags.txt

@@ -1,9 +1 @@
-fails:StringIO#reopen when passed [Object, Integer] reopens self with the passed Object in the passed mode
-fails:StringIO#reopen when passed [Object, Integer] does not taint self when the passed Object was tainted
-fails:StringIO#reopen when passed [Object, Integer] tries to convert the passed Object to a String using #to_str
-fails:StringIO#reopen when passed [Object, Integer] raises a TypeError when the passed Object can't be converted to a String
-fails:StringIO#reopen when passed [Object, Integer] raises an Errno::EACCES when trying to reopen self with a frozen String in write-mode
 fails:StringIO#reopen when passed [Object, Integer] raises a TypeError when trying to reopen self with a frozen String in truncate-mode
-fails:StringIO#reopen when passed [Object, Integer] raises a RuntimeError when trying to reopen self with a frozen String in truncate-mode
-fails:StringIO#reopen when passed [Object, Integer] does not raise IOError when passed a frozen String in read-mode
-fails:StringIO#reopen does not truncate the content even when the StringIO argument is in the truncate mode

truffle/src/main/ruby/core/shims.rb

@@ -212,3 +212,19 @@ def num_bytes=(count)
   end
 
 end
+
+class IO
+
+  RDONLY = 0
+  WRONLY = 1
+  RDWR = 2
+
+  CREAT = 512
+  EXCL = 2048
+  NOCTTY = 131072
+  TRUNC = 1024
+  APPEND = 8
+  NONBLOCK = 4
+  SYNC = 128
+
+end