Add build number to datapath version and --version output from programs.

m4/nx-build.m4

@@ -0,0 +1,48 @@
+# -*- autoconf -*-
+
+# Copyright (c) 2008 The Board of Trustees of The Leland Stanford
+# Junior University
+#
+# We are making the OpenFlow specification and associated documentation
+# (Software) available for public use and benefit with the expectation
+# that others will use, modify and enhance the Software and contribute
+# those enhancements back to the community. However, since we would
+# like to make the Software available for broadest use, with as few
+# restrictions as possible permission is hereby granted, free of
+# charge, to any person obtaining a copy of this Software to deal in
+# the Software under the copyrights without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+#
+# The name and trademarks of copyright holder(s) may NOT be used in
+# advertising or publicity pertaining to the Software or any
+# derivatives without specific, written prior permission.
+
+dnl NX_BUILDNR([NUMBER])
+dnl
+dnl If NUMBER is empty, substitutes BUILDNR with 0 and sets C
+dnl preprocessor variable BUILDNR to "".
+dnl
+dnl If NUMBER is nonempty, substitutes a Makefile variable BUILDNR
+dnl with NUMBER, and sets a C preprocessor variable BUILDNR to
+dnl "+buildNUMBER".
+AC_DEFUN([NX_BUILDNR],
+  [AC_SUBST([BUILDNR], 
+            [m4_if([$1], [], [0], [$1])])
+   AC_DEFINE([BUILDNR],
+             [m4_if([$1], [], [""], ["+build$1"])], 
+             [Official build number.])])