--- VirtualBox-5.0.12/src/VBox/Runtime/r3/posix/thread2-posix.cpp.orig
+++ VirtualBox-5.0.12/src/VBox/Runtime/r3/posix/thread2-posix.cpp
@@ -65,7 +65,7 @@
 #elif defined(RT_OS_SOLARIS) || defined(RT_OS_HAIKU)
         sched_yield();
 #else
-        if (!pthread_yield())
+        if (!sched_yield())
 #endif
         {
             LogFlow(("RTThreadSleep: returning %Rrc (cMillies=%d)\n", VINF_SUCCESS, cMillies));
@@ -104,7 +104,7 @@
 #elif defined(RT_OS_SOLARIS) || defined(RT_OS_HAIKU)
         sched_yield();
 #else
-        if (!pthread_yield())
+        if (!sched_yield())
 #endif
             return VINF_SUCCESS;
     }
@@ -130,10 +130,8 @@
 #endif
 #ifdef RT_OS_DARWIN
     pthread_yield_np();
-#elif defined(RT_OS_SOLARIS) || defined(RT_OS_HAIKU)
-    sched_yield();
 #else
-    pthread_yield();
+    sched_yield();
 #endif
 #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
     u64TS = ASMReadTSC() - u64TS;