Allow uname values to be overridden by the environment

# First get uname entries that we use below

MACHINE=`(uname -m) 2>/dev/null` || MACHINE="unknown"

RELEASE=`(uname -r) 2>/dev/null` || RELEASE="unknown"

SYSTEM=`(uname -s) 2>/dev/null`  || SYSTEM="unknown"

VERSION=`(uname -v) 2>/dev/null` || VERSION="unknown"

[ "$MACHINE" ] || MACHINE=`(uname -m) 2>/dev/null` || MACHINE="unknown"

[ "$RELEASE" ] || RELEASE=`(uname -r) 2>/dev/null` || RELEASE="unknown"

[ "$SYSTEM" ] || SYSTEM=`(uname -s) 2>/dev/null`  || SYSTEM="unknown"

[ "$BUILD" ] || VERSION=`(uname -v) 2>/dev/null` || VERSION="unknown"

# Now test for ISC and SCO, since it is has a braindamaged uname.