C:\Keil\ARM\RV31\INC\RTX_lib.c(54): error: #20: identifier "OS_TIMER" is undefinedC:\Keil\ARM\RV31\INC\RTX_lib.c(126): error: #20: identifier "OS_TVAL" is undefinedC:\Keil\ARM\RV31\INC\RTX_lib.c(135): error: #20: identifier "OS_TOVF" is undefined