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.

gcc/java/
	* decl.c (poplevel): Don't access TREE_TYPE of BLOCKs.
	* expr.c (build_jni_stub): Likewise.

From-SVN: r174300