libarchive: make single bit bitfields unsigned to avoid clang 16 warning

libarchive: make single bit bitfields unsigned to avoid clang 16 warning

Clang 16 introduced a warning about single bit bitfields in structs,
which is triggered by various declarations in libarchive:

    contrib/libarchive/libarchive/archive_write_set_format_7zip.c:1541:13: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
                    file->dir = 1;
                              ^ ~
    contrib/libarchive/libarchive/archive_write_set_format_iso9660.c:5127:15: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
                    isoent->dir = 1;
                                ^ ~
    contrib/libarchive/libarchive/archive_write_set_format_iso9660.c:5213:14: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
            isoent->dir = 1;
                        ^ ~
    contrib/libarchive/libarchive/archive_write_set_format_iso9660.c:5214:18: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
            isoent->virtual = 1;
                            ^ ~
    contrib/libarchive/libarchive/archive_write_set_format_iso9660.c:7149:18: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
            isoent->virtual = 1;
                            ^ ~
    contrib/libarchive/libarchive/archive_write_set_format_iso9660.c:7435:32: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
                    iso9660->zisofs.detect_magic = 1;
                                                 ^ ~
    contrib/libarchive/libarchive/archive_write_set_format_iso9660.c:7495:25: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
            iso9660->zisofs.making = 1;
                                   ^ ~
    contrib/libarchive/libarchive/archive_write_set_format_iso9660.c:7496:26: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
            iso9660->zisofs.allzero = 1;
                                    ^ ~
    contrib/libarchive/libarchive/archive_write_set_format_iso9660.c:7702:28: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
                            iso9660->zisofs.allzero = 1;
                                                    ^ ~
    contrib/libarchive/libarchive/archive_write_set_format_iso9660.c:7871:25: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
                    zisofs->header_passed = 1;
                                          ^ ~
    contrib/libarchive/libarchive/archive_write_set_format_iso9660.c:7894:24: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
                            zisofs->initialized = 1;
                                                ^ ~

Signed one-bit bitfields can only have values -1 and 0, but the intent
here is to use the fields as booleans, so make them unsigned.

This has also been sent upstream.

MFC after:	3 days

(cherry picked from commit 67ecab6f50ff29e9bda340be1e9d2acc963c9a2b)