maint.mk: enhance useless header checks

maint.mk: enhance useless header checks

Libvirt was mistakenly using <intprops.h> instead of "intprops.h"
in one place; when I fixed that, I was surprised to get a
syntax-check failure from an unused header.

* top/maint.mk (_sc_header_without_use): Check both include
styles.
(sc_prohibit_assert_without_use)
(sc_prohibit_close_stream_without_use)
(sc_prohibit_getopt_without_use)
(sc_prohibit_quotearg_without_use)
(sc_prohibit_quote_without_use)
(sc_prohibit_long_options_without_use)
(sc_prohibit_inttostr_without_use)
(sc_prohibit_ignore_value_without_use)
(sc_prohibit_error_without_use, sc_prohibit_xalloc_without_use)
(sc_prohibit_hash_without_use, sc_prohibit_cloexec_without_use)
(sc_prohibit_posixver_without_use, sc_prohibit_same_without_use)
(sc_prohibit_hash_pjw_without_use)
(sc_prohibit_safe_read_without_use)
(sc_prohibit_argmatch_without_use)
(sc_prohibit_canonicalize_without_use)
(sc_prohibit_root_dev_ino_without_use)
(sc_prohibit_openat_without_use)
(sc_prohibit_c_ctype_without_use)
(sc_prohibit_signal_without_use)
(sc_prohibit_stdio--_without_use)
(sc_prohibit_stdio-safer_without_use)
(sc_prohibit_strings_without_use)
(sc_prohibit_intprops_without_use)
(sc_prohibit_stddef_without_use)
(sc_prohibit_xfreopen_without_use): Update clients.

Signed-off-by: Eric Blake <eblake@redhat.com>