kernel32: Add UmsThreadYield stub.

dlls/kernel32/kernel32.spec

@@ -1524,7 +1524,7 @@
 # @ stub -arch=x86_64 uaw_wcsicmp
 # @ stub -arch=x86_64 uaw_wcslen
 # @ stub -arch=x86_64 uaw_wcsrchr
-# @ stub -arch=x86_64 UmsThreadYield
+@ stdcall -arch=x86_64 UmsThreadYield(ptr)
 # @ stub -arch=x86_64 __misaligned_access
 @ stdcall -i386 -private UTRegister(long str str str ptr ptr ptr) krnl386.exe16.UTRegister
 @ stdcall -i386 -private UTUnRegister(long) krnl386.exe16.UTUnRegister

dlls/kernel32/process.c

@@ -4354,6 +4354,16 @@ BOOL WINAPI SetUmsThreadInformation(PUMS_CONTEXT ctx, UMS_THREAD_INFO_CLASS clas
     return FALSE;
 }
 
+/***********************************************************************
+ *           UmsThreadYield   (KERNEL32.@)
+ */
+BOOL WINAPI UmsThreadYield(void *param)
+{
+    FIXME( "%p: stub\n", param );
+    SetLastError( ERROR_CALL_NOT_IMPLEMENTED );
+    return FALSE;
+}
+
 /**********************************************************************
  *           BaseFlushAppcompatCache     (KERNEL32.@)
  */

include/winbase.h

@@ -2654,6 +2654,7 @@ WINBASEAPI BOOL        WINAPI UnlockFileEx(HANDLE,DWORD,DWORD,DWORD,LPOVERLAPPED
 #define                       UnlockResource(handle) ((handle), 0)
 #define                       UnlockSegment(handle) GlobalUnfix((HANDLE)(handle))
 WINBASEAPI BOOL        WINAPI UnmapViewOfFile(LPCVOID);
+WINBASEAPI BOOL        WINAPI UmsThreadYield(void *);
 WINBASEAPI HRESULT     WINAPI UnregisterApplicationRestart(void);
 WINBASEAPI BOOL        WINAPI UnregisterWait(HANDLE);
 WINBASEAPI BOOL        WINAPI UnregisterWaitEx(HANDLE,HANDLE);