--- winpr/libwinpr/synch/synch.h	2025-04-14 21:11:41.000000000 +0800
+++ winpr/libwinpr/synch/synch.h	2025-05-08 20:34:34.000000000 +0800
@@ -48,6 +48,10 @@
 #define winpr_sem_t sem_t
 #endif
 
+#ifdef __APPLE__
+#include <AvailabilityMacros.h>
+#endif
+
 struct winpr_mutex
 {
 	WINPR_HANDLE common;
@@ -76,7 +80,7 @@
 #include <fcntl.h>
 #define TIMER_IMPL_POSIX
 
-#elif defined(__APPLE__)
+#elif defined(__APPLE__) && MAC_OS_X_VERSION_MIN_REQUIRED > 1060
 #define TIMER_IMPL_DISPATCH
 #include <dispatch/dispatch.h>
 #else

# Original code here is just wrong:
--- winpr/libwinpr/synch/timer.c	2025-04-14 21:11:41.000000000 +0800
+++ winpr/libwinpr/synch/timer.c	2025-05-08 20:42:08.000000000 +0800
@@ -655,7 +655,7 @@
 	if (Type != HANDLE_TYPE_TIMER)
 		return FALSE;
 
-#if defined(__APPLE__)
+#if defined(TIMER_IMPL_DISPATCH)
 	{
 		WINPR_TIMER* timer = (WINPR_TIMER*)Object;
 		if (timer->running)