[Bug libstdc++/65118] Android target build is broken with "guard.cc:36:22: fatal error: syscall.h: No such file or directory"

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65118

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
That's been there since 2008, why hasn't it caused a problem before now?