[OE-core] [PATCH] gcc-7.inc: add new warning "Wnot-cross-compiler"

[Khem Raj]

On Wed, Jul 19, 2017 at 7:26 PM, Andre McCurdy <armccurdy at gmail.com> wrote:
> On Wed, Jul 19, 2017 at 2:57 PM, Bystricky, Juro
> <juro.bystricky at intel.com> wrote:
>>> precisely, the problem is that some host compiler may silently ignore
>>> unknown warnings and some host may not be using gcc as default system
>>> compiler at all e.g. mageia distro and may be more in future.
>>
>> Yes, it does not nor it attempts to solve all toolchain issues.
>> The expectation is that a compiler will choke on an unrecognized option.
>> For example, gcc will do the following:
>>
>> $ gcc -Wnot-cross-compiler hello_world.c
>> gcc: error: unrecognized command line option ‘-Wnot-cross-compiler’
>>
>> As for non-gcc compilers: yes, they may silently ignore unrecognized options
>> (which IMHO is just wrong). In that case the new options does not work as intended,
>> but it does no harm either.
>> Anyway, the intended use was to add something like this a .conf file:
>>
>> TARGET_CC_ARCH_append_class-target = " -Wnot-cross-compiler -Werror=not-cross-compiler"
>
> Personally, I think we already try to pass too much via CC or the
> compiler command line (e.g. -fdebug-prefix-map=XXX). Has there ever
> been any thought of OE providing a toolchain wrapper, which could pass
> these kinds of housekeeping options to the underlying toolchain while
> keeping build logs clean and without the worry that CC, CFLAGS, etc
> get ignored or clobbered by a custom Makefile somewhere?

we could do it by providing customized spec file
but this will not be good for external toolchains