inner macro not expanded after hash hash

[danmar]

Example code:

#define FOO(a) CAT(DO, STUFF)(1,2)
#define DOSTUFF(a, b)  CAT(3, 4)
#define CAT(a, b) a##b

FOO(1)

simplecpp output:

 UTIL_CAT  (  3  , 4  )

gcc -E output:

34