add cmake script to write version files

.gitignore

@@ -24,3 +24,6 @@ debian/*.log
 # etags and cscope db
 tags
 cscope.out
+
+# generated version files
+*/cmake/BareosVersion.cmake

write_version_files.cmake

@@ -0,0 +1,43 @@
+# BAREOS® - Backup Archiving REcovery Open Sourced
+#
+# Copyright (C) 2019-2019 Bareos GmbH & Co. KG
+#
+# This program is Free Software; you can redistribute it and/or modify it under
+# the terms of version three of the GNU Affero General Public License as
+# published by the Free Software Foundation and included in the file LICENSE.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc., 51
+# Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+cmake_minimum_required(VERSION 3.0)
+
+set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/cmake"
+                      "${CMAKE_CURRENT_LIST_DIR}/core/cmake"
+                      "${CMAKE_CURRENT_LIST_DIR}/webui/cmake")
+
+find_package(Git)
+include(BareosVersionFromGit)
+
+include(BareosVersion OPTIONAL RESULT_VARIABLE BareosVersionFile)
+if(BareosVersionFile STREQUAL "NOTFOUND")
+  if(GIT_DESCRIBE_VERSION)
+    set(VERSION_STRING "${GIT_DESCRIBE_VERSION}")
+  else()
+    message(FATAL_ERROR "No version information from git available.")
+  endif()
+endif()
+
+set(version_file_header "# autogenerated by write_version_files.cmake")
+set(version_file_contents "${version_file_header}\nset(VERSION_STRING    \"${GIT_DESCRIBE_VERSION}\")\nset(VERSION_TIMESTAMP \"${GIT_COMMIT_TIMESTAMP}\")\n")
+
+foreach(subdir "core" "webui")
+  set(version_file_name "${CMAKE_CURRENT_LIST_DIR}/${subdir}/cmake/BareosVersion.cmake")
+  message(STATUS "Writing ${version_file_name}")
+  file(WRITE ${version_file_name} "${version_file_contents}")
+endforeach()