libctf: remove ctf_malloc, ctf_free and ctf_strdup

libctf: remove ctf_malloc, ctf_free and ctf_strdup

These just get in the way of auditing for erroneous usage of strdup and
add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free?
ctf_strdup or strdup?"

ctf_malloc and ctf_free usage has not reliably matched up for many
years, if ever, making the whole game pointless.

Go back to malloc, free, and strdup like everyone else: while we're at
it, fix a bunch of places where we weren't properly checking for OOM.
This changes the interface of ctf_cuname_set and ctf_parent_name_set,
which could strdup but could not return errors (like ENOMEM).

New in v4.

include/
	* ctf-api.h (ctf_cuname_set): Can now fail, returning int.
	(ctf_parent_name_set): Likewise.
libctf/
	* ctf-impl.h (ctf_alloc): Remove.
	(ctf_free): Likewise.
	(ctf_strdup): Likewise.
	* ctf-subr.c (ctf_alloc): Remove.
	(ctf_free): Likewise.
	* ctf-util.c (ctf_strdup): Remove.

	* ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not
	ctf_free; strdup, not ctf_strdup.
	(ctf_dtd_delete): Likewise.
	(ctf_dvd_delete): Likewise.
	(ctf_add_generic): Likewise.
	(ctf_add_function): Likewise.
	(ctf_add_enumerator): Likewise.
	(ctf_add_member_offset): Likewise.
	(ctf_add_variable): Likewise.
	(membadd): Likewise.
	(ctf_compress_write): Likewise.
	(ctf_write_mem): Likewise.
	* ctf-decl.c (ctf_decl_push): Likewise.
	(ctf_decl_fini): Likewise.
	(ctf_decl_sprintf): Likewise.  Check for OOM.
	* ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not
	ctf_free; strdup, not ctf_strdup.
	(ctf_dump_free): Likewise.
	(ctf_dump): Likewise.
	* ctf-open.c (upgrade_types_v1): Likewise.
	(init_types): Likewise.
	(ctf_file_close): Likewise.
	(ctf_bufopen_internal): Likewise.  Check for OOM.
	(ctf_parent_name_set): Likewise: report the OOM to the caller.
	(ctf_cuname_set): Likewise.
	(ctf_import): Likewise.
	* ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc;
	free, not ctf_free; strdup, not ctf_strdup.
	(ctf_str_free_atom): Likewise.
	(ctf_str_create_atoms): Likewise.
	(ctf_str_add_ref_internal): Likewise.
	(ctf_str_remove_ref): Likewise.
	(ctf_str_write_strtab): Likewise.