--- cl-original/kernel/thread.h	2021-06-24 14:55:26.169597780 +0200
+++ cl-patched/kernel/thread.h	2021-06-24 14:58:02.485568178 +0200
@@ -2979,6 +2979,8 @@
    "Posix is portable in the sense that you can use a forklift to move the
     printed volumes around" */
 
+#include <sched.h>
+
 #define THREADFUNC_DEFINE( name, arg )	void *name( void *arg )
 #define THREAD_CREATE( function, arg, threadHandle, syncHandle, status ) \
 			{ \
@@ -3016,7 +3018,11 @@
   #if defined( __linux__ ) && !defined( __USE_GNU )
 	void pthread_yield( void );
   #endif /* Present but not prototyped unless GNU extensions are enabled */
-  #define  THREAD_YIELD()		pthread_yield()
+  
+  #if defined( __linux__ ) && ( OSVERSION > 3 )
+       #define  THREAD_YIELD()		sched_yield()
+  #endif
+
 #endif /* Not-very-portable Posix portability */
 #define THREAD_SLEEP( ms )		{ \
 								struct timeval tv = { 0 }; \