make TS_BLOCK a substructure of TS_BASE
gcc/
* tree.c (initialize_tree_contains_struct): Mark TS_BLOCK as
TS_BASE instead of TS_COMMON.
(find_decls_types_r): Check for TS_TYPED structure before looking at
TREE_TYPE.
* tree.h (struct tree_block): Inherit from tree_base, not tree_common.
Add chain field.
(BLOCK_CHAIN): Use new chain field.
gcc/c-family/
* c-common.c (warning_candidate_p): Check for BLOCKs.