* support.cs: Api for Pair to set a value. Despite the fact that
the variables are public the MS C# compiler refuses to compile
code that accesses the field if the variable is part of a foreach
statement.
* statement.cs (Fixed): Begin implementation of the fixed
statement.
(Block.AddVariable): Return the VariableInfo on success and null
on failure instead of true/false.
* cs-parser.jay (foreach): Catch errors on variables already
defined (we were ignoring this value before) and properly unwind
the block hierarchy
(fixed_statement): grammar for the fixed statement.
svn path=/trunk/mcs/; revision=2183
