Add CMake platform-check (32/64-bit) (includes new test-variable ${PLATFORM} that defines X86/X64 basesystem)

--HG--
branch : trunk

CMakeLists.txt

@@ -30,6 +30,7 @@ endif()
 #
 
 include(CheckIncludeFiles)
+include(cmake/FindPlatform.cmake)
 include(cmake/FindPCHSupport.cmake)
 
 if(WIN32)

cmake/FindPlatform.cmake

@@ -0,0 +1,16 @@
+# default to x86 platform.  We'll check for X64 in a bit
+SET(PLATFORM X86)
+
+# This definition is necessary to work around a bug with Intellisense described
+# here: http://tinyurl.com/2cb428.  Syntax highlighting is important for proper
+# debugger functionality.
+
+IF(CMAKE_SIZEOF_VOID_P MATCHES 8)
+    MESSAGE(STATUS "Detected 64-bit platform.")
+    if(WIN32)
+      ADD_DEFINITIONS("-D_WIN64")
+    ENDIF()
+    SET (PLATFORM X64)
+ELSE()
+    MESSAGE(STATUS "Detected 32-bit platform.")
+ENDIF()