Fix Windows CI build errors and add System Design section to README

CMakeLists.txt:
- Add CMAKE_CXX_SCAN_FOR_MODULES=OFF to fix yaml-cpp modmap errors
  with CMake 3.28+ and MinGW on Windows
- Add SPDLOG_USE_STD_FORMAT=ON to fix spdlog consteval errors
  with Clang and C++20 on Windows

README.md:
- Add C++ System Design section covering memory management,
  concurrency patterns, design patterns, and system architecture

Author: behnamasadi

CMakeLists.txt

@@ -11,6 +11,10 @@ set(CMAKE_CXX_STANDARD 20) # Replace 20 with the version number of the latest C+
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
+# Disable C++20 module scanning (CMake 3.28+)
+# Dependencies like yaml-cpp, spdlog don't support C++20 modules yet
+set(CMAKE_CXX_SCAN_FOR_MODULES OFF)
+
 if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
     message("using Visual Studio C++")
 
@@ -553,8 +557,12 @@ endif()
 
 if(ENABLE_SPDLOG)
     message("\n########################################## spdlog ##########################################\n")
-# Fetch spdlog
-FetchContent_Declare(
+
+  # Use std::format (C++20) instead of bundled fmt to avoid Clang/Windows consteval bug
+  set(SPDLOG_USE_STD_FORMAT ON CACHE BOOL "Use std::format instead of bundled fmt")
+
+  # Fetch spdlog
+  FetchContent_Declare(
     spdlog
     GIT_REPOSITORY https://github.com/gabime/spdlog.git
     GIT_TAG        v1.14.1  # Use a specific tag, branch, or commit
@@ -567,9 +575,6 @@ FetchContent_Declare(
 
   # Link spdlog to your target
   target_link_libraries(spdlog_example PRIVATE spdlog::spdlog)
-  
-  # Optionally, if you want to disable spdlog's automatic formatting, add the following:
-  # target_compile_definitions(MyExecutable PRIVATE SPDLOG_FMT_EXTERNAL)
 
 else()
     message("spdlog is not enabled")
@@ -625,6 +630,6 @@ endif()
 
 
 
-if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/src/main.cpp")
-    add_executable(main src/main.cpp)
-endif()
+# if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/src/main.cpp")
+#     add_executable(main src/main.cpp)
+# endif()

README.md

@@ -382,6 +382,24 @@ This change ensures that VSCode uses the "Ninja Multi-Config" generator by defau
 - [isocpp](https://isocpp.org/wiki/faq/coding-standards)
 - [Bjarne Stroustrup's C++ Style](https://www.stroustrup.com/bs_faq2.html)
 
+## [C++ System Design](#)
+
+- [Memory Management Strategies (Pool, Arena, Slab Allocators)](docs/system_design/memory_management.md)
+- [Object-Oriented Design Patterns (Factory, Singleton, Observer, Strategy)](docs/system_design/design_patterns.md)
+- [Concurrency Patterns (Thread Pool, Producer-Consumer, Active Object)](docs/system_design/concurrency_patterns.md)
+- [Lock-Free and Wait-Free Data Structures](docs/system_design/lock_free_structures.md)
+- [Cache-Friendly Data Structures and Data-Oriented Design](docs/system_design/cache_friendly_design.md)
+- [Plugin Architecture and Dynamic Loading](docs/system_design/plugin_architecture.md)
+- [Event-Driven Architecture and State Machines](docs/system_design/event_driven_state_machines.md)
+- [API and ABI Design for C++ Libraries](docs/system_design/api_abi_design.md)
+- [SOLID Principles in C++](docs/system_design/solid_principles.md)
+- [Real-Time Systems Design](docs/system_design/realtime_systems.md)
+- [Embedded Systems Design](docs/system_design/embedded_systems.md)
+- [Game Engine Architecture](docs/system_design/game_engine_architecture.md)
+- [High-Performance Computing (HPC) Patterns](docs/system_design/hpc_patterns.md)
+- [Serialization and Deserialization (Protobuf, FlatBuffers)](docs/system_design/serialization.md)
+- [Error Handling Strategies and Fault Tolerance](docs/system_design/error_handling_strategies.md)
+
 ## [VSCode](#)
 
 - [`tasks.json`, `settings.json`, `launch.json`](docs/vscode.md)