CDRIVER-2083 Raise a warning when using CMake on non-Windows platform

Author: bjori

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 2.8)
+cmake_minimum_required(VERSION 3.1)
 
 project (libmongoc C)
 
@@ -19,6 +19,10 @@ option(ENABLE_AUTOMATIC_INIT_AND_CLEANUP "Enable automatic init and cleanup (GCC
 option(ENABLE_CRYPTO_SYSTEM_PROFILE "Use system crypto profile (OpenSSL only)" OFF)
 option(ENABLE_TRACING "Turn on verbose debug output" OFF)
 
+if (NOT WIN32)
+    message(WARNING "CMake support is experimental and may not produce production quality artifacts")
+endif ()
+
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${PROJECT_SOURCE_DIR}/build/cmake)
 
 include(InstallRequiredSystemLibraries)

NEWS

@@ -1,6 +1,8 @@
 Next Release
 ============
 
+  * Minimum required CMake version has been increased to 3.1.
+  * CMake remains experimental on non-Windows platforms and issues a warning now
   * Experimental support for wire compression.
     * Support for snappy and zlib. MongoDB 3.4 only supports snappy, while zlib
       support is expected in MongoDB 3.6. Wire compression is still experimental