i think it works

code/win32/user32.c

@@ -0,0 +1,20 @@
+// user32.c - minimal user32 stubs (no window manager yet)
+#include <stdint.h>
+
+// Screen blit is the only graphical primitive available at this stage.
+extern void SysScreenBlit(int x, int y, int w, int h, const uint32_t* pixels);
+
+// syscall.dll
+extern void SysYield(void);
+
+void BitBlt(int x, int y, int w, int h, const uint32_t* pixels) {
+    SysScreenBlit(x, y, w, h, pixels);
+}
+
+// Message loop stubs - always return 0.
+int GetMessage(void* msg, void* hwnd, unsigned int min, unsigned int max) {
+    (void)msg; (void)hwnd; (void)min; (void)max;
+    SysYield();
+    return 0;
+}
+int DispatchMessage(const void* msg) { (void)msg; return 0; }