[Bug pch/68176] [4.9/5/6 Regression] all pch tests fail on eglibc systems (with bits/predefs.h)

[nix at esperi dot org.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68176

--- Comment #11 from Nix <nix at esperi dot org.uk> ---
Confirmed fixed (properly this time).