Re: 32bit builds on x86-64 host.

[Al Viro <viro@ftp.linux.org.uk>]

On Mon, Oct 29, 2007 at 07:32:31PM -0400, Dave Jones wrote:
> Before the arch merge, I frequently would test 32bit compiles
> by doing make ARCH=i386 {bzImage/modules/file.o}
> 
> Since commit 47572387d58a9584c60ebbbdee56fc92c627f16f
> how does one do this?

Same.  Top-level makefile kludges around that:

SRCARCH         := $(ARCH)

# for i386 and x86_64 we use SRCARCH equal to x86
SRCARCH := $(if $(filter x86_64 i386,$(SRCARCH)),x86,$(SRCARCH))

and then plays with both ARCH and SRCARCH.  Note
# If a arch/$(SRCARCH)/Kconfig.$(ARCH) file exist use it
ifneq ($(wildcard $(srctree)/arch/$(SRCARCH)/Kconfig.$(ARCH)),)
        Kconfig := arch/$(SRCARCH)/Kconfig.$(ARCH)
else
        Kconfig := arch/$(SRCARCH)/Kconfig
endif

in scripts/kconfig/Makefile, BTW - now we use arch/x86/Kconfig.i386 and
arch/x86/Kconfig.x86_64 as starting points for ARCH=i386 and ARCH=x86_64
resp.