--- ../src/swipl-devel/packages/ssl/ssl4pl.c	2025-03-17 14:01:04.910450514 +0100
+++ ../src/swipl-devel/packages/ssl/ssl4pl.c	2025-03-17 14:00:55.760439225 +0100
@@ -47,6 +47,10 @@
 #include <pthread.h>
 #endif
 
+#if defined(__WINDOWS__) || defined (__CYGWIN__)
+#include <windows.h>
+#endif
+
 #include <openssl/x509v3.h>
 #include <openssl/ssl.h>
 #include <openssl/bn.h>
