rbutil: Create git version information at build time.

Change-Id: Iaf701f4d64d6852423f6a28a753b27abc43477e2

utils/cmake/gitversion.cmake

@@ -0,0 +1,58 @@
+#
+#             __________               __   ___.
+#   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+#   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+#   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+#   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+#                     \/            \/     \/    \/            \/
+#
+# All files in this archive are subject to the GNU General Public License.
+# See the file COPYING in the source tree root for full license agreement.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+
+find_package(Git QUIET)
+
+execute_process(COMMAND ${GIT_EXECUTABLE} rev-parse --verify --short=10 HEAD
+                OUTPUT_VARIABLE GIT_HASH
+                ERROR_QUIET)
+
+# Check whether we got any revision (which isn't
+# always the case, e.g. when someone downloaded a zip
+# file from Github instead of a checkout)
+if ("${GIT_HASH}" STREQUAL "")
+    set(GIT_HASH "N/A")
+else()
+    execute_process(
+        COMMAND git diff --quiet --exit-code
+        RESULT_VARIABLE GIT_DIFF_EXITCODE)
+
+    string(STRIP "${GIT_HASH}" GIT_HASH)
+    if (${GIT_DIFF_EXITCODE})
+        set(GIT_DIFF "M")
+    endif()
+endif()
+
+string(TIMESTAMP TODAY "%y%m%d")
+set(VERSION "
+#ifndef GITVERSION
+#define GITVERSION \"${GIT_HASH}${GIT_DIFF}-${TODAY}\"
+#define GITHASH \"${GIT_HASH}${GIT_DIFF}\"
+#define BUILDDATE \"${TODAY}\"
+#endif
+")
+
+if(EXISTS ${OUTFILE})
+    file(READ "${OUTFILE}" _version)
+else()
+    set(_version "")
+endif()
+
+if (NOT "${VERSION}" STREQUAL "${_version}")
+    file(WRITE "${OUTFILE}" "${VERSION}")
+endif()
+
+message("-- Revision: ${GIT_HASH}${GIT_DIFF}")
+