* tree-flow.h: Remove some prototypes.
* tree.h: Remove some protypes, add a couple.
* tree.c (using_eh_for_cleanups_flag, using_eh_for_cleanups,
using_eh_for_cleanups_p): Add interface routines for front ends.
* tree-eh.h: New file. Add protoptyes.
* tree-eh.c (using_eh_for_cleanups_p, using_eh_for_cleanups): Delete.
(add_stmt_to_eh_lp_fn): Make static.
(lower_try_finally): Use new using_eh_for_cleanups_p.
* emit-rtl.c: Include tree-eh.h.
* gimple.h: Include tree-eh.h.