Changed "CONFIGURATION SECTION" to contain #ifndef so you can define these macros before including this header, not necessarily change them in the file. (Cherry pick from v1)
Changed "CONFIGURATION SECTION" to contain #ifndef so you can define these macros before including this header, not necessarily change them in the file. (Cherry pick from v1)

GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator,GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator,GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator