feat: Improve search, evaluation, and move ordering

This commit introduces several enhancements to the search algorithm, evaluation function, and move ordering techniques to improve the engine's performance.

- Makefile: Added -pthread flag to ensure proper threading support.
- search.hpp: Reduced PV move array size, added nodes counter and seldepth.
- move_ordering.hpp: Changed moveOrder signature to include ttMove, added see prototype.
- CMakeLists.txt: Added threading support and platform-specific configurations.
- eval.h: Removed unused popcount and lsb implementations, added MoveStack class, added trace function prototype.
- main.cpp: Implemented benchmark mode, fixed bestmove output, added eval command.
- move_ordering.cpp: Implemented SEE (Static Exchange Evaluation) for move ordering.
- search.cpp: Implemented iterative deepening with aspiration windows, quiescence search, LMR (Late Move Reduction), and TT probing.
- eval.cpp: Rewrote evaluation function with material, pawn structure, mobility, king safety, space, tempo, and PSQT (Piece-Square Table) evaluation. Added trace function to print evaluation breakdown.

Author: winapiadmin

CMakeLists.txt

@@ -23,3 +23,37 @@ set(SOURCES
 
 # Define the executable
 add_executable(${PROJECT_NAME} ${SOURCES})
+
+# Threading support
+find_package(Threads REQUIRED)
+target_link_libraries(${PROJECT_NAME} Threads::Threads)
+
+# Platform-specific threading configurations
+if(WIN32)
+    if(MSVC)
+        # Windows with MSVC - uses Windows threading API
+        target_compile_definitions(${PROJECT_NAME} PRIVATE WIN32_LEAN_AND_MEAN)
+    elseif(MINGW)
+        # MinGW on Windows - uses pthread
+        target_compile_definitions(${PROJECT_NAME} PRIVATE _WIN32_WINNT=0x0601)
+        # MinGW might need explicit pthread linking
+        if(CMAKE_THREAD_LIBS_INIT)
+            target_link_libraries(${PROJECT_NAME} ${CMAKE_THREAD_LIBS_INIT})
+        endif()
+    endif()
+elseif(UNIX)
+    # Unix/Linux systems - uses pthread
+    if(CMAKE_THREAD_LIBS_INIT)
+        target_link_libraries(${PROJECT_NAME} ${CMAKE_THREAD_LIBS_INIT})
+    endif()
+    # Some older systems might need explicit -pthread flag
+    if(CMAKE_USE_PTHREADS_INIT)
+        target_compile_options(${PROJECT_NAME} PRIVATE -pthread)
+        target_link_options(${PROJECT_NAME} PRIVATE -pthread)
+    endif()
+endif()
+
+# Optional: Add atomic library support for older compilers
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS "4.9")
+    target_link_libraries(${PROJECT_NAME} atomic)
+endif()

Makefile

@@ -13,7 +13,7 @@ all: $(EXEC)
 
 # Linking the object files into the executable
 $(EXEC): $(OBJ)
-	$(CXX) $(LDFLAGS) -o $(EXEC) $(OBJ)
+	$(CXX) $(LDFLAGS) -pthread -o $(EXEC) $(OBJ)
 
 # Rule to build object files from source files
 %.o: %.cpp