[PATCH] kbuild: automatically append a short string to the version based upon the git commit

If CONFIG_AUTO_LOCALVERSION is set, the user is using a git-based tree, and the
current HEAD is not referred to by any tags in .git/refs/tags/, append -g and
the first 8 characters of the commit to the version string.  This makes it
easier to use git-bisect, and/or to do a daily build, without trampling on your
older, working builds, or accidentally setting up conflicting sets of modules.

Signed-off-by: Ryan Anderson <ryan@michonline.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Makefile

diff --git a/Makefile b/Makefile
index d01b004..c6aae86 100644
--- a/Makefile
+++ b/Makefile
@@ -548,6 +548,26 @@
 # images. Default is /boot, but you can set it to other values
 export	INSTALL_PATH ?= /boot
 
+# If CONFIG_LOCALVERSION_AUTO is set, we automatically perform some tests
+# and try to determine if the current source tree is a release tree, of any sort,
+# or if is a pure development tree.
+#
+# A 'release tree' is any tree with a git TAG associated
+# with it.  The primary goal of this is to make it safe for a native
+# git/CVS/SVN user to build a release tree (i.e, 2.6.9) and also to
+# continue developing against the current Linus tree, without having the Linus
+# tree overwrite the 2.6.9 tree when installed.
+#
+# Currently, only git is supported.
+# Other SCMs can edit scripts/setlocalversion and add the appropriate
+# checks as needed.
+
+
+ifdef CONFIG_LOCALVERSION_AUTO
+	localversion-auto := $(shell $(PERL) $(srctree)/scripts/setlocalversion $(srctree))
+	LOCALVERSION := $(LOCALVERSION)$(localversion-auto)
+endif
+
 #
 # INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
 # relocations required by build roots.  This is not defined in the