cmake: make sure build works with cmake < 2.8.3

cmake/compat_2.8.3 contains files required for cmake versions < 2.8.3
and CheckCmakeCompat includes them if necessary.

CMakeParseArguments.cmake and FindPackageHandleStandardArgs.cmake are
taken from the modules shipped with cmake.

cmake/CheckCmakeCompat.cmake

@@ -0,0 +1,35 @@
+# Central location to check for cmake (version) requirements
+#
+#=============================================================================
+# Copyright 2012 Bernhard Miklautz <bmiklautz@thinstuff.com>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#=============================================================================
+
+# Enable compatibility for cmake < 2.8.3
+if(${CMAKE_VERSION} VERSION_LESS 2.8.3)
+        set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_SOURCE_DIR}/cmake/compat_2.8.3/)
+endif()
+
+# If MONOLITHIC_BUILD is used with cmake < 2.8.8 build fails
+if (MONOLITHIC_BUILD)
+	if(${CMAKE_VERSION} VERSION_LESS 2.8.8)
+		message(FATAL_ERROR "CMAKE version >= 2.8.8 required for MONOLITHIC_BUILD")
+	endif()
+endif(MONOLITHIC_BUILD)
+
+# GetGitRevisionDescription requires FindGit which was added in version 2.8.2
+# build won't fail but GIT_REVISION is set to n/a
+if(${CMAKE_VERSION} VERSION_LESS 2.8.2)
+	message(WARNING "GetGitRevisionDescription reqires (FindGit) cmake >= 2.8.2 to work properly - GIT_REVISION will be set to n/a")
+endif()