[Bug preprocessor/15638] gcc should have option to treat missing headers as fatal

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15638

--- Comment #18 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Lucia Huang from comment #17)
> Hi, 
> Is there an option to revert this change?  To generate an error or warning
> for a missing header?  Thanks.

What is the use case for having this as a non fatal error?  I cannot think of
one. The main reason why is a fatal error is due missing an include will cause
cascading errors latter on.