[Vala] defining types (analogous to #define Addr ulong )

[Charles Hixson <charleshixsn earthlink net>]

Is there any way in Vala to define type names equivalent to built-in types?

I have a use case where I'd like to be able to try a particular type, 
and then later globally change my mind if I had picked the wrong size.  
But I don't want to change, e.g., all instances of "int", but only those 
being used for a particular purpose.  In C I'd do this with a #define or 
with a typedef.  In D I'd use an alias (typedef being broken the last 
time I checked).  But if Vala has some similar feature, I haven't been 
able to find it in the docs.