HEADS UP: incompatible change with bsd.prefs.mk for i386

[Richard PALO <richard%netbsd.org@localhost>]

Just to save anybody else the same frustration, the following commit:
> Date:		Tue Nov 18 23:36:07 UTC 2014
>
> Modified Files:
> 	pkgsrc/mk: bsd.prefs.mk
>
> Log Message:
> Sync MACHINE_ARCH -> GNU_ARCH mapping table with NetBSD. Most noticable
> change outside ARM is going to i486 as platform name for x86.
will render toxique any i386 pkgsrc installation using pkgsrc gcc 
requiring more or less a full rebuild (or better, bootstrap).

pkg_rolling-replace only aggravates things as anything that used to look 
for the i386-*-* flavours of files now bomb in strange and obscure ways 
looking for i486-*-*, until gcc and a real lot of packages using gnu 
configure are rebuilt with dependencies like libgcc_s.so and libstdc++.so.