Don't assert and leak memory if failing during argument collection. Once you have a -D option or a -include foo option, you need to clean up the arrays those are accumulated in if you die before they're collected and handled.

#define a() x
a()
a ()
#define b(p) p
x/**/b(1)/**/x
x/**/b (1)/**/x
x/**/b()/**/x
#define c(p,q) p/**/q
x/**/c(1,2)/**/x
x/**/c(1)/**/x
x/**/c()/**/x