Fix PPROCESSOR_NUMBER issue

Author: lauzadis

CMakeLists.txt

@@ -115,6 +115,12 @@ if (XCODE)
     set_property(GLOBAL PROPERTY XCODE_EMIT_EFFECTIVE_PLATFORM_NAME OFF)
 endif()
 
+if (WIN32)
+    # Ensure Windows SDK exposes newer APIs like PPROCESSOR_NUMBER
+    # https://github.com/aws/aws-iot-device-sdk-cpp-v2/issues/427
+    add_compile_definitions(_WIN32_WINNT=0x0601)
+endif()
+
 # Create a single static library that combines all the individual libs
 # We do this to work around issues with link order when including multiple
 # `staticLibraries` in the cinterop file.