[regressions] Re: kbuild: save ARCH & CROSS_COMPILE when building a kernel

[Ingo Molnar <mingo@elte.hu>]

Sam,

that arch-cache thing introduced in:

 5755433: kbuild: save ARCH & CROSS_COMPILE when building a kernel

isnt working very well in my experience.

1) it's a nuisance in cross-builds (it broke several cross-build scripts 
   of mine)

2) it makes it hard to switch from 32-bit x86 builds to 64-bit ones: 
   previously i only needed 'make ARCH=i386 defconfig' and off we went - 
   now i have to add a 'make mrproper' step.

3) it can also get stuck:

  phoenix:~/linux/linux> make mrproper
  Makefile:571: /home/mingo/tip/arch/no/Makefile: No such file or directory
  make: *** No rule to make target `/home/mingo/tip/arch/no/Makefile'.  Stop.

  phoenix:~/linux/linux> cat include/generated/*
  no

  phoenix:~/linux/linux> 

 There's no way out of this state, only if i manually remove 
 include/generated. (i suspect this is fixable)

Dunno - why isnt the .config enough in terms of determining which 
architecture we are on? If we want more info we should put it into the 
.config - not some other hidden state. I do think a single file should 
carry all 'configuration state' - that makes it easier to reproduce 
things, etc. etc. Everything else is really just hindering us.

	Ingo