final+varasm: Change return type of predicate functions from int to bool

final+varasm: Change return type of predicate functions from int to bool

Also change some internal variables to bool and change return type of
compute_alignments to void.

gcc/ChangeLog:

	* output.h (leaf_function_p): Change return type from int to bool.
	(final_forward_branch_p): Ditto.
	(only_leaf_regs_used): Ditto.
	(maybe_assemble_visibility): Ditto.
	* varasm.h (supports_one_only): Ditto.
	* rtl.h (compute_alignments): Change return type from int to void.
	* final.cc (app_on): Change return type from int to bool.
	(compute_alignments): Change return type from int to void
	and adjust function body accordingly.
	(shorten_branches):  Change "something_changed" variable
	type from int to bool.
	(leaf_function_p):  Change return type from int to bool
	and adjust function body accordingly.
	(final_forward_branch_p): Ditto.
	(only_leaf_regs_used): Ditto.
	* varasm.cc (contains_pointers_p): Change return type from
	int to bool and adjust function body accordingly.
	(compare_constant): Ditto.
	(maybe_assemble_visibility): Ditto.
	(supports_one_only): Ditto.