other/9471: [pch] #pragma system_header vs. precompiled headers

[bkoz@redhat.com]

>Number:         9471
>Category:       other
>Synopsis:       [pch] #pragma system_header vs. precompiled headers
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jan 28 03:46:01 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Benjamin Kosnik
>Release:        gcc-3.4 20030125
>Organization:
>Environment:
rh linux 7.3
>Description:
This is odd behavior, but just annoying.

If I create a pch this way:
%COMP.sh "-x c++-header -Winvalid-pch" ostream

I get:
ostream:43:13: warning: #pragma system_header ignored outside include file

However, if I create a pch by doing

cat > precomp_ostream.hh
#include <ostream>

I don't get the error. 

These cases, which are identical input, should give identical output.

>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: