Crash: digit separator in bitint

[ehaas]

//aro-args -std=c23
int x = 1'2wb;

/Users/ehaas/local/zig-macos-x86_64-0.12.0-dev.1536+6b9f7e26c/lib/std/fmt.zig:1971:17: 0x10c1ac1a5 in charToDigit (arocc)
        else => return error.InvalidCharacter,
                ^
/Users/ehaas/local/zig-macos-x86_64-0.12.0-dev.1536+6b9f7e26c/lib/std/math/big/int.zig:318:23: 0x10c299e28 in setString (arocc)
            const d = try std.fmt.charToDigit(ch, base);
                      ^
/Users/ehaas/local/zig-macos-x86_64-0.12.0-dev.1536+6b9f7e26c/lib/std/math/big/int.zig:2786:9: 0x10c2997b7 in setString (arocc)
        try m.setString(base, value, limbs_buffer, self.allocator);
        ^
/Users/ehaas/source/arocc/src/aro/Parser.zig:8163:35: 0x10c2131d2 in bitInt (arocc)
        error.InvalidCharacter => unreachable, // digits validated by Tokenizer
                                  ^