add bits for AIX to correctly set MACHINE_ARCH and OS_VERSION, so that

MACHINE_GNU_PLATFORM is set to something sane. tested with AIX 4.3.3
and 5.1.

mk/bsd.prefs.mk

@@ -1,4 +1,4 @@
-# $NetBSD: bsd.prefs.mk,v 1.180 2005/02/11 16:11:36 tv Exp $
+# $NetBSD: bsd.prefs.mk,v 1.181 2005/02/17 07:11:59 grant Exp $
 #
 # Make file, included to get the site preferences, if any.  Should
 # only be included by package Makefiles before any .if defined()
@@ -172,6 +172,25 @@ OS_VERSION!=		echo ${OS_VERSION} | sed -e 's/^V//'
 LOWER_OPSYS?=		osf${OS_VERSION}
 LOWER_VENDOR?=		dec
 
+.elif ${OPSYS} == "AIX"
+LOWER_ARCH!=		_cpuid=`/usr/sbin/lsdev -C -c processor -S available | sed 1q | awk '{ print $$1 }'`; \
+			if /usr/sbin/lsattr -El $$_cpuid | grep ' POWER' >/dev/null 2>&1; then \
+				echo rs6000; \
+			else \
+				echo powerpc; \
+			fi
+MACHINE_ARCH?=		${LOWER_ARCH}
+.  if exists(/usr/bin/oslevel)
+_OS_VERSION!=		/usr/bin/oslevel
+.  else
+_OS_VERSION!=		echo `${UNAME} -v`.`${UNAME} -r`
+.  endif
+OS_VERSION!=		echo ${_OS_VERSION} | sed -e 's,\([0-9]*\.[0-9]*\).*,\1,'
+LOWER_OS_VERSION=	${OS_VERSION}
+LOWER_OPSYS_VERSUFFIX=	${_OS_VERSION}
+LOWER_OPSYS?=		aix
+LOWER_VENDOR?=		ibm
+
 .elif !defined(LOWER_OPSYS)
 LOWER_OPSYS!=		echo ${OPSYS} | tr A-Z a-z
 .endif