[PATCH 0/2] MR6955: include, ntdll: Use %fs/%gs prefixes instead of a separate .byte 0x64/.byte 0x65.

[Brendan Shanks (＠bshanks)]

Part of this patch was [submitted 3 years ago](https://list.winehq.org/mailman3/hyperkitty/list/[e-mail]/threa...) by Keno Fischer, but was not merged.

The separate `.byte` causes `gas` to [emit incorrect DWARF line info](https://sourceware.org/bugzilla/show_bug.cgi?id=28699), which caused a [crash in rr](https://github.com/rr-debugger/rr/issues/3009). Using `%fs`/`%gs` is also clearer.