Revert "Increase CMake minimum version to 3.0"

This reverts commit ff3cf934.

Turns out distros only a year old still use CMake 2.8x

CMakeLists.txt

@@ -45,7 +45,12 @@ if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_BINARY_DIR})
 	endif()
 endif()
 
-cmake_minimum_required(VERSION 3.0.0)
+cmake_minimum_required(VERSION 2.8)
+
+if(NOT (${CMAKE_VERSION} VERSION_LESS 3.0))
+	# keep until CMake-3.0 is min requirement
+	cmake_policy(SET CMP0043 OLD)
+endif()
 
 if(NOT EXECUTABLE_OUTPUT_PATH)
 	set(FIRST_RUN TRUE)
@@ -71,8 +76,18 @@ set_property(DIRECTORY APPEND PROPERTY COMPILE_DEFINITIONS_RELWITHDEBINFO  NDEBU
 #-----------------------------------------------------------------------------
 # Set policy
 
-# Simplify variable reference and escape sequence evaluation
-cmake_policy(SET CMP0053 NEW)
+# see "cmake --help-policy CMP0003"
+# So library linking is more sane
+cmake_policy(SET CMP0003 NEW)
+
+# So BUILDINFO and BLENDERPATH strings are automatically quoted
+cmake_policy(SET CMP0005 NEW)
+
+# So syntax problems are errors
+cmake_policy(SET CMP0010 NEW)
+
+# Input directories must have CMakeLists.txt
+cmake_policy(SET CMP0014 NEW)
 
 #-----------------------------------------------------------------------------
 # Load some macros.
@@ -484,6 +499,11 @@ endif()
 # Apple
 
 if(APPLE)
+	if(${CMAKE_VERSION} VERSION_LESS 3.0) # else breaks setting CMP0043 policy
+		cmake_minimum_required(VERSION 2.8.8)
+		cmake_policy(VERSION 2.8.8)
+	endif()
+
 	if(NOT CMAKE_OSX_ARCHITECTURES)
 		set(CMAKE_OSX_ARCHITECTURES x86_64 CACHE STRING
 		"Choose the architecture you want to build Blender for: i386, x86_64 or ppc"
@@ -493,8 +513,12 @@ if(APPLE)
 	execute_process(COMMAND uname -r OUTPUT_VARIABLE MAC_SYS) # check for actual system-version
 	if(${MAC_SYS} MATCHES 15)
 		set(OSX_SYSTEM 10.11)
+		# throw an error here, older cmake cannot handle 2 digit subversion!
+		cmake_minimum_required(VERSION 3.0.0)
 	elseif(${MAC_SYS} MATCHES 14)
 		set(OSX_SYSTEM 10.10)
+		# throw an error here, older cmake cannot handle 2 digit subversion!
+		cmake_minimum_required(VERSION 3.0.0)
 	elseif(${MAC_SYS} MATCHES 13)
 		set(OSX_SYSTEM 10.9)
 	elseif(${MAC_SYS} MATCHES 12)

intern/ghost/test/CMakeLists.txt

 
-cmake_minimum_required(VERSION 3.0.0)
+cmake_policy(SET CMP0003 NEW)
+cmake_policy(SET CMP0005 NEW)
+
+cmake_minimum_required(VERSION 2.8)
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/../../..//build_files/cmake/Modules")