From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
Subject: Re: [U-Boot] [PATCH] fdt: Enhance dts/Makefile to be all things to
 all men
Date: Wed, 29 May 2013 11:02:45 -0600
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To: Wolfgang Denk <wd-ynQEQJNshbs@public.gmane.org>
Cc: u-boot-review-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, Devicetree Discuss <devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org>, U-Boot Mailing List <u-boot-0aAXYlwwYIKGBzrmiIFOJg@public.gmane.org>, Tom Warren <twarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>, Tom Rini <trini-l0cyMroinI0@public.gmane.org>
List-Id: devicetree@vger.kernel.org

On 05/28/2013 03:08 PM, Wolfgang Denk wrote:
> Dear Simon Glass,
> 
> In message <1369769778-12455-1-git-send-email-sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> you wrote:
>>
>> Some device tree files use the word 'linux' which gets replaced with '1' by
>> many version of gcc, including version 4.7. So undefine this.
> 
> I think this is not a good way to address this issue.  The GCC
> documentation (section "System-specific Predefined Macros" [1])
> desribes how this should be handled.  The "correct" (TM) way to fix
> this is by adding "-ansi" or any "-std" option that requests strict
> conformance to the compiler/preprocessor command line.
> 
> [1] http://gcc.gnu.org/onlinedocs/cpp/System_002dspecific-Predefined-Macros.html#System_002dspecific-Predefined-Macros

-ansi at least was considered when the Linux kernel patches for dtc+cpp
support were being developed, but it was rejected. While it possibly
does solve this specific issue fine, there were other more general
problems; IIRC (and I might not) it completely changes the way macro
expansion happens, which results in it being pretty useless. Hence, "-x
assembler-with-cpp" was chosen over e.g. "-ansi".