Fix Windows build: add conditional headers for sys/socket.h

- Add #ifdef _WIN32 to use winsock2.h/ws2tcpip.h instead of sys/socket.h
- Update build.sh to support both Linux and Windows/MSYS2
- Auto-detect platform and configure accordingly (--host=x86_64-w64-mingw32 for Windows)
- All 22 tests pass on Linux

lib/debug_config.h

@@ -3,11 +3,16 @@
  * Provides flexible control over debug output without recompilation
  */
 
-#ifndef DEBUG_CONFIG_H
-#define DEBUG_CONFIG_H
-
-#include <sys/socket.h>   // struct sockaddr_storage
-#include <stddef.h>       // size_t
+#ifndef DEBUG_CONFIG_H
+#define DEBUG_CONFIG_H
+
+#ifdef _WIN32
+    #include <winsock2.h>
+    #include <ws2tcpip.h>
+#else
+    #include <sys/socket.h>   // struct sockaddr_storage
+#endif
+#include <stddef.h>       // size_t
 #include <stdint.h>
 #include <stddef.h>
 #include <time.h>