[Bug other/91085] fixincludes breaks

[xry111 at mengyan1223 dot wang via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91085

--- Comment #17 from Xi Ruoyao <xry111 at mengyan1223 dot wang> ---
Revised patch, matching __has_include(...):

https://gcc.gnu.org/pipermail/gcc-patches/2021-June/573789.html