[Bug bootstrap/121407] Patches to fix building docs under makeinfo 4.8

[kirill at korins dot ky via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121407

--- Comment #2 from Kirill A. Korinsky <kirill at korins dot ky> ---
Andrew, not sure.

A hunk for intrinsic.texi and gfortran.texi probably new.