compiler: don't write sink constants to C header file

    
    Reviewed-on: https://go-review.googlesource.com/89815

From-SVN: r257049

gcc/go/gofrontend/MERGE

-0bbc03f81c862fb35be3edee9824698a7892a17e
+016ea21c4cba324c6ea6424da7988c6f985e671b
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/gogo.cc

@@ -4633,7 +4633,9 @@ Gogo::write_c_header()
 
       if (no->is_type() && no->type_value()->struct_type() != NULL)
 	types.push_back(no);
-      if (no->is_const() && no->const_value()->type()->integer_type() != NULL)
+      if (no->is_const()
+	  && no->const_value()->type()->integer_type() != NULL
+	  && !no->const_value()->is_sink())
 	{
 	  Numeric_constant nc;
 	  unsigned long val;