[Bug pch/108732] Pre-compiled headers cannot be output to /dev/null

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108732

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
>I maintain a number of builds that do similar invocations to verify that each 
>header file is self-contained.

You could just do:
gcc -xc -include header.h /dev/null -o /dev/null -c

Which works better and will always work when modules become standard ...