This patch makes it easy to programmatically get at the kernel
makefile's idea of the kernel version from external scripts and
makefiles with something like V=`make kernelrelease`.

Alternatives include parsing Makefile (errorprone and broken by things
like localversion) and running the C preprocessor on version.h (which
requires a) building version.h somewhere and b) is really ugly).

From: Matt Mackall <mpm@selenic.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>