Dependency update
Prevent infinite inline recursion
More inline examples
Inline return handling

This needed the backend to support merging n-way phi blocks.
Nested inlining should also be supported.
Handle inline void functions
Free up memory used in function inlining
Optimise single-return/no-phi inline functions
Updated inline TODO
Partial change of gen_* functions to const
Changes to statement gen functions - const stmt *
Note debug locations in inline-todo
Change iteration for statement walking
Inline heuristic decision
Note more inline flags in TODO_INLINE