PCH is used only for the first header

[Loren James Rittle]

In article <67B5ACB373D0D411B9BD00508BD951A702831394@nnsmsx30.inn.intel.com>:

>	#include "a.h"
>	#include "b.h"

> only pch for "a.h" can be used and ignored for "b.h" and subsequent ones.
> I.e. if I have "b.h.gch" and do not have "a.h.gch" then "b.h.gch" will not
> be used.

> Is it supposed behavior? I did not find a word about this in online docs.

>From invoke.texi (which is used to build the info file for your local
install and the WWW content once/if a branch with the feature is released):

"A precompiled header file can be used only when these conditions apply:
[...] Only one precompiled header can be used in a particular compilation."