[Skiboot] [PATCH] Makefile: Separate CFLAGS and HOSTCFLAGS warning flags

[Stewart Smith]

Samuel Mendoza-Jonas <sam.mj at au1.ibm.com> writes:
> Some warnings may not be supported in older host compilers - remove them
> from HOSTCFLAGS but keep them for CFLAGS
>
> Removed from HOSTCFLAGS:
> 	-Wjump-misses-init
> 	-Wsuggest-attribute=const
> 	-Wsuggest-attribute=noreturn
> 	-Wstack-usage=1024

I've ended up fixing this a bit differently, by just checking for each
of these if the compiler supports it, also for the abiv1 flag.

So... theoretically, we can build with more GCC versions now.

I've also added in detection of if  we have flags to prevent altivec and
VSX instructions from being generated, as using them is a Bad Idea(TM).